Mostly things you did when you were younger that you wouldnt do again.

When I was a little kid growing up in the midwest we had alot of thorns and "stickerburrs" that would cause flats all the time. After patching a tube a million times and finally replacing it we would cut the old tube and line the inside of the tire with it. I think one of my bmx bikes had like four layers like this. When you are 12 you arent a weight weenie lol.

Another good one using used motor oil to lube everything lol.

I remember laying my bike down and standing on the wheel to straighten it (doh!)

i beat the hell out of so many department store bikes and somehow managed to make them last and/or piece together something so i could still ride.