I've recently found out about New Zealand's DineAid:

Dine out at a participating restaraunt during November and December 2008, and at the end of your meal you will notice a voluntary donation of just $2 per table has been added to the bill. (separate to any other gratuity or tips you may chose to leave). Participating restaurants send the donations back to DineAid at the end December and then distributed to those who may need a bit of a ‘helping hand’ during the festive season. Wellington City Mission is one of the charity beneficaries!

The beauty of StreetSmart is its simplicity. It is an innovative, easy fundraising scheme which works during the holiday months when people begin to think about those less fortunate than themselves.

At participating restaurants, with the benefit of a tablecard, or a reference on the menu, a voluntary £1 is added to the table bill at the end of the meal during the months of November and December. At the end of each month, the restaurant passes on the total money raised to StreetSmart. We then use all of those £1s to support reputable charities in that city. So participating London diners are helping out London organisations, and Newcastle diners are helping organisations in the North East.

And remember: since all StreetSmart's running and operational costs are generously paid for by our sponsors, every penny in every £1 raised goes directly to the people who need it!