The game I play for the moment is Hidden & Dangerous. It must be one of the top games when it comes to number of crashes / hour (AGA not included ). If the game don't crash on every level Im surprised and if it don't crash for two levels I will stop playing and go and buy a lottery ticket. If I should rank the top two bugs then I would pick:

1 Trip on the invisible turtle and fall out the level.
2 Try to kill the enemy behind your best friend with your machine-gun.

Well..., I'm still playing .