Wikipedia has some good ones on the Whose Line
- Changed Letters: The performers enact a scene; however, the performers must substitute one letter for another in all spoken words, as specified by the host. (For example, if 'F' is substituted for 'B', lines like "I fruised my futt on the fack porch" might be spoken.)
- If You Know What I Mean: Several performers improvise a scene in which they make up as many ambiguous euphemisms as they can.
- Improbable Mission: Two performers are super-secret agents a la Mission: Impossible. A third performer is the voice on the tape, who gives them their assignment: a mundane task (e.g. get dressed or mow the lawn).
- Moving People: Two performers enact a scene, but cannot move on their own. Instead, two audience members move them into different positions as they act out the scene.
- Weird Newscasters: One performer is the lead anchor of a news show, with the others acting as co-host, sports anchor, and weather anchor. The host gives each performer (except the lead anchor) a quirky personality to be used in the scene.
and any with props would be hilarious, if you could get props...which would be doubtful.