As a kid/teen, I was into model cars, both ½4 scale display pieces, and 1/10 scale electric R/C cars. The former had me dong all sorts of plastic work, and the latter involved all sorts of things, including more soldering than I care to remember (no other way to get a nice, low-loss connection between the MOSFET speed control and the motor; plugs increase resistance) and suspension mods.
After wasting about a decade between being an electrician in the Navy and doing a series of drudge-jobs afterwards, I got back into CNC machining, and have built everything from audio panels (for recording studios) to parts for rockets. It’s not uncommon for me to have to build my own tools either. This on top of doing my own work on my cars (head gaskets, shocks… but I will not tear apart a transmission!), and occasional carpentry.
I enjoy building all sorts of things. I think my next project may be making a MakerBot or RepRap. They are cheap, and I already know the G-codes to program them (they use the same language as the OKK 50-taper mill and Haas SL-20 lathe I spend most of my workday on) so I could probably be up and running for under $300 easily.