Sorry to bring this a little off topic, but I only had one (actively participating) experience with DnD, and games of this sort.
Dowe and I were at another friend's house, who was playing DM. Since it was our first time, we were nervous (lulz, guttermind) but were told to "have fun with it!! Don't take it so seriously!" We cracked two (lame but OVERLY AWESOME jokes) and our DM got mad :( and stopped the game. We only played for about.... 20 minutes? I really want to play shit like this, but I don't want to piss on anybody's hard work or aggravate them.