many years ago both me and my partner decided we should donate 1% of our earnings to some good cause (there seems to be a common 'meme' of giving one percent of earnings - googling turns up a lot of different ideas). it was a good idea, and we did it once, i think, before forgetting. then a few years passed, we remembered, and did it once again. and then a few more years passed and we felt bad and got our acts togeth…
http://en.wikipedia.org/wiki/Tithe
And I'd consider putting 10% of my income towards social good a much better goal. It's not one that I always hit, but I think almost all of us could stand to carve this portion of our income out of our budgets, especially when it can so greatly benefit the causes we really care for. EFF is certainly one of mine.