If I am not the only Jelly answering your question, you could have a fun hour or so, replying to all the respondents!
So, c’mon Jellies, stop lurking, and give @Carly something to read/smile/laugh!

I generally read. If you don’t have a book handy, there is usually a book store in pretty much every major airport in the country.

What do you call a Jamaican Proctologist?

A Haiti hottie

Walk around (the shops) or read
But following @rebbel‘s advice…Don’t you think Jim Caviezel is one of the sexiest men ever?

I was stuck at the airport a few weeks ago. I was glad I hadn’t went through security yet, that way I was able to walk around outside, lounge around in the terminal, read, people watch, walk around some more, etc.

I wander about, look at the other travellers, get something to eat and mostly read.

Watch the planes takeoff and land. I could do that all day…

@Aesthetic_Mess I do think so.

This just happened to me. I played games on my phone and read a book. Sometimes I just watched people.

@Keep_on_running I know!
Watching the planes take off is an excellent suggestion.

No one mentions power walking around and around and around. It makes a good exercise unit and also passes the time.

I figure this is free time at the airport and ask myself “What can I do here that I can’t do anywhere else?” I try to resist using my lap top since I can do that any time. I the time to get a little exercise and learn the area. I enjoy watching the people rushing around. Look how they’re dressed. Look at that guy over there. Yes, him… You just know he is a jerk. Right? Look at her. Man she must be high maintenance! That quiet guy is very polite. Is he wearing a ring? Figures.
Go to a place that is boarding and watch who tries to cut in line. Yep! Sometimes stereotypes are right on. In fact you could have predicted those three were going to do it. They left their cups on the seats too. Pigs.

People watch, walk, learn, look for local items, window shop.
If you need to eat avoid the chain restaurants and look for anything local.
Enjoy.

Teach yourself to juggle. Get three napkins or tissues and wrap them around three smaller, heavier objects. You could use balled-up paper or something. They should be light enough that they won’t fall very quickly. The napkin/tissue should act like a tail and slow the descent rate, and give you more to grab when practicing.

Last time it happened, I was recovering from a broken toe. So naturally I kept running the toe over with the luggage cart.
I finally decided that the whole thing was stupid and parked myself in the airport bookstore. That’s where I found The Hitchhiker’s Guide to the Galaxy.

Go to one of the airport bars. Do some people watching. Flirt with some people of interest. Go back to the bar (with a new friend).

Get a map of the world and try to cross off as many places as you can. You cross off a location when you’ve met someone from there.

Find a newspaper. Do the crossword. Then go find someone with the same paper and ask if they’re going to do the crossword, and if not, can you. When they give it to you finish the crossword in 15seconds and have fun with them thinking you’re some kind of genius.

If you’re good at accents I’m really not go meet people in an accent and pretend you’re from that place.

Roll some nickles around and watch people trying to find out where they came from.

Put a quarter and a penny on the ground next to each other. Watch to see if people pick up just the quarter, or the quarter and the penny.

Find two doors next to each other that lead to the same place. Make little signs that say “Men” and “Women” and stick them on the doors. Watch to see if anyone obeys them.

Walk up to a terminal that’s going to board soon. Sit down next to some people and wait for the attendant to start making announcements over the speaker; take out your ticket and look at it. Then run off like you’re at the wrong terminal and you’re going to miss your flight. Yell something like, “this is just Botswana all over again” as you run away.

Buy a really cheap pair of reading glasses from any of the shops. Break them. Then walk up to different terminals looking like you have no idea where you are. Pull out your ticket and look up at the information on the board, then back to your ticket. Keep squinting like you can’t see good. Eventually pull out your broken glasses and act like you’re trying to make do, but it’s obviously not working. *Bonus points if someone steps up to help you.

Leave a small cup of water on the floor somewhere. High traffic areas are better, but harder to place the cup without being obvious. See how long it lasts before getting kicked over or cleaned up by janitors.

Write little notes on pieces of paper. Something like, “meet me at the insert location at 20 minutes from current time. See ya there! ;) *hearts” Sign it something like “Amber” or “Elise”. Make like 50 of them and start leaving them around where they’ll be found (i.e. seats). Go to the location you gave at that time. See if anyone shows up looking around all weird.

This one’s pretty much the same as above… Find a pay phone. Find out the number for the pay phone. Write the number on like 50 strips of paper and leave them around the airport. Then sit near the phone and see if it rings. If you want to come up with something to say, and answer it, that could be fun too.

Make paper airplanes and leave them around. Wait around for about 10 minutes to see if anyone throws them.

Do a good deed.

Last time I was waiting 6 hours for a flight I just wrote in my journal, later i went for a coffee and watched people come and go. You can really have a blast with yourself ;-) One thing in particular that helps me cope with slow moving time is thinking to myself “time is constantly moving forward”. No matter how bored you are, time never stops, it.constantly.moves.forward. no matter what you do time is passing, the knowledge or the awareness, that sooner or later the time for you to leave will come can be liberating.

Masturbate.

Pull out my laptop and swear at whatever hoops are required to get wireless access. That usually kills all the time I need to.

If you’re going the right direction, try sleeping. You might spare yourself some jet lag later. I recommend clutching your belongings to yourself.

Talk to myself and walk around in circles.

Coincidentally I just wrote a facebook update a few hours ago about how much I like Delta Gates 1 and 2 at Laguardia in NY, because they have table seating at the gate with an ipad screen for every table where you can access the internet and order a meal from the nearby restaurant and the waiter runs it out to you while you wait by the gate. My chicken pesto panini was delicious yesterday. It’s the only airport I don’t mind arriving early.

When I get delayed a few hours part of the time I usually watch the news if it is playing at the gates, check my facebook, and text some friends who are always good for a laugh and to pass time. Sometimes I am able to strike up a conversation with someone sitting nearby. If there is a restaurant maybe sit down have a coke if I am not very hungy. Restaurants with bars might be more likely to have someone to talk to if you are interested in having some conversation. I can kill some time watchng planes taxi and take off, but that only holds my interest for a half hour at most.

In Atlanta you can stay at their “minute suites” basically a sofa/daybed to relax and sleep for a few hours. I assume other large airports have them also, especially if they do a lot of international flights. I think it is a small room just large enough for the bed and to put your luggage down. I assume they have full bathroom facilites also.

I depends on how much carry-on I have.

If it’s light: I walk. Get a coffee. Get some food. Walk somemore. Visit the shops. I try not to sit.

If it’s heavy: Pace near my carry-on. Talk to strangers. Fiddle. Play a game. Eat a snack. I’m more caonservative with my walking if my carry-ons are heavy. Depending on the wait…if it’ll be a while I’d go to a restaurant to eat.

I drink martinis. If I don’t feel like drinking I read a book.

Strike up a conversation with a Brazilian model.

@SpatzieLover Fiddle? I want to travel with you from now on.

Dream of owning my own helicopter, “haha…fuck you losers!”

Shop in the duty free shop

Sudoku puzzles and coffee.

Lots of things. If the airport has a decent transit area like Heathrow does, go shopping in the duty free shops. Or have a meal at a real restaurant. Is there a little lounge area where you can pull out your laptop and slingshot birds at green pigs inside wooden fortresses?

@Esedess, did you gain your mastery of boredom in the classroom, in the workplace, or in church?

I read.
Sleep.
Talk to my husband (my usual travel partner).
Talk to other travellers.
People watch.
Go for coffee.
Shop.

Read, eat, drink, try to sleep. Mostly reading.

Last time I was in an international airport, we were all sitting around waiting and waiting… there was us on one side and facing us in the chairs opposite (about three/four feet away) were a young man and his girlfriend, she was sitting on his knee fast asleep and a little kid sitting next to them but not with them.

Suddenly, there was this huge fart noise! HUGE noise.

It wasn’t the kid. It was the girlfriend and we and the boyfriend fell about laughing. She didn’t wake up so we had a good laugh at her expense!

I always carry my needlework with me, but since I got my laptop, I am never at a loss for something to do.

Once, there was a snow delay in Denver for several hours. I was traveling with a small child, and when the other parents saw the crafts and games I played, using discarded newspapers, paper plates, and other found stuff, I was soon entertaining about a dozen children. The parents even provided snacks for everyone.

It was Christmas season, and I taught them how to make newspaper Christmas trees.

When it became clear that the plane, that was supposed to arrive and take our group from Shanghai to Beijing, was not going to arrive until morning, the airport passed out blankets and we tried to get as comfortable as possible to sleep. At 2 in the morning they brought out steaming kettles of soup and ladled out bowls of it to anyone who wanted it. That gesture took away the annoyance we were feeling and those who could, went back to sleep. We were on a vacation/education trip and the experience was just that

@Jeruba Haha! Never really thought of it before, but definitely school… =]

I read. Easy to find reading materials at almost any airport.

Yep, depends on the time/situation, morning, afternoon, night, how much time you have to kill etc.
I had a midnight flight out of SFO a couple years ago, since it was so late and I wanted to sleep as it was a long overseas flight my friend and I opted for a few cocktails and a nice walk around before we were confined for the next 13 hours.

Makeout.

Sit in a corner and laugh at all of the goofy people who will always be at airports.