The funniest place would have to be my friend's bedroom while a cop was knocking at his front door.

I lived in a duplex apartment - my adjacent neighbors were smokers but not my roomie. So we were hitting it in my friend's bedroom when a cop knocks on the door. We had ducked inside the room and were talking about how fucked up the whole situation was. I glanced out the bedroom door and saw a female cop walking away towards the direction of my apartment after knocking a few times! Ack!

A few nervous minutes of hiding out ensued. Then I called my roommate and nervously asked him if the cop was still there. He said no - they were looking for some other person who lived in a different apartment.