If/Then
You can play this game with as few as three people, but the more the merrier!
Make sure each player has a piece of scrap paper and a pen.
Each player should write an "If" statement --anything open-ended that starts with the word "if." For example, a player might write "If I embezzle from my company" or "If the sky falls," or "If cows are much smarter than we think..." Whatever, really.
Then, all players should fold their papers and pass them to the left.
The players who recieve the papers should not look at the "If" statement. All players should write a "then" statement.
Then, all players should pass their papers to the left.
Open the papers and read aloud the sentences: first "If" then "then." The results are often suprising and amusing.
You can do this all night with the right group! Mix it up once in a while so the same people are not completing each other's sentences.