A four person game (five if another student is the 'mouse-meister') from Abbleside Primary School that reinforces multiplication facts:
http://www.amblesideprimary.com/ambleweb/mentalmaths/gameshow.html

Here is a simpler version, with smaller numbers:
http://www.amblesideprimary.com/ambleweb/mentalmaths/gameshoweasy.html

And a similar game, also from Ambleside Primary School:
http://www.amblesideprimary.com/ambleweb/mentalmaths/tabletrees.html