Pokerstars are running a series of "tournaments" ranging from $1-$1000 buyin.
There are no prizes for these tournaments: all entry fees will go to the Red Cross. However Pokerstars themselves will match all donations, making this an easy way to donate to the Haiti relief effort AND have your donation doubled.
A quality gesture from a quality site.
Link to a Mirror article about this: PokerStars Haiti relief effort nears half million - mirror.co.uk