Bughouse Chess

From BoardGameGeek:

Bughouse Chess is a variation of chess played with two teams of two people on two chess boards. Chess clocks are used, generally with 5 minute time controls. Team members sit beside each other playing opposite colors. Each player plays his opponent as in standard chess, except that whenever a piece is captured, it is given to the teammate. The teammate can then decide to play a normal move, or place the captured piece on any unoccupied square of the board (exception: pawns cannot be placed on the 1st or 8th rank). Team members have to work together and against the clock to win. The first person to lose by checkmate or time loses for his or her team, thus ending both games.