My friend does this thing called "Smokes for Jokes." You get some very, very interesting responses.
One time a homeless guy told him the following joke:
"Okay, so a black and a white guy go into a bar. Then the black guy gets up and leaves. So it's just the white guy in the bar. Then, he gets up and leaves, too.
*a moment of tense silence as he looks at him with a very serious look on his face*
I think it was you."
My friend just sort of looked at the guy like, "Uhh, okay buddy .. here's your cigarette." He then proceeded to run into the venue screaming "DOOD OMG HAHAHAHAHA CHECK THIS OUT" and told everyone what just happened.