Bridge with Deuces Wild
This game was invented by Jeff Rubens and published in the June 1975 issue of The Bridge World.
It is played exactly like Contract Bridge, except that in the play, any deuce (two) may be played to any trick.
So the rule is that if you can follow suit to the lead you must either do so or play a deuce. If you cannot follow suit you may play any card.
Deuces have no special power to win tricks - the normal rules apply in that respect. But of course, if you hold the 2 of trumps, you can ruff with it and win the trick (if no one else ruffs higher), even if you have cards in the suit led.
Leading a deuce has no special effect. Players who have the suit of the deuce must either follow suit or play another deuce, as usual.