The experiment was successful! It succeeded in every way I had hoped it would: I donated much more to charity than I ever had before; I feel great about it; I learned something about my spending patterns; and I had fun in 2010. A lot of fun. (Certain others can attest.)
It also had a further benefit I had not predicted: I learned more about charities and effective philanthropy.
I find that I like this method of determining the amount to donate. It seems less arbitrary than choosing a percentage of income, which would leave me wondering whether I picked the right percentage. For the past year, every gift for myself was also a gift for someone else. That feels right, and I'm going to keep doing it.
(In case you're curious: the list of charities.)
(Not wrong, but a little odd to see my real name getting tweeted everywhere. I'm @zestyping on Twitter.)