a couple of times in games with friends, but it’s not fun so I generally don’t. There was this one board game (like Monopoly) I played with a specific friend as a child and we ALWAYS cheated. Whenever one wasn’t looking the other one would just rob the bank. And it was fairly obvious because all of a sudden we’d have an extra 1,000,000,000 next to the 231,500 that we had last turn. But it was good fun.
I remember playing cards with a boy a couple of years younger than me once, and I always showed him the 6s and 9s upside down whenever it suited me and he bought it hehe ;)
But I don’t remember cheating in the last 25 years or so…