I also give blood once a year. It's one of those winwin cases where there is a benefit for oneself as well as for others:
Blood donation
The studies related to this have some methodological issues but overall the effect size is so large, and the cost and risks so low, that it is worth inclusion. Several studies have indicated that, for men, regular blood donation results in a massive reduction in heart attack.[1][2][3] Other studies have found no such relation.[4] There are also additional health benefits to blood donation.[5] These are just some of the studies on this subject, but on balance after reviewing the evidence, I can say that donating blood once a year is almost certainly worth it if you're a man. Donating too often is probably bad for you though.
http://lesswrong.com/lw/jrt/lifestyle_interventions_to_increase_longevity/
What are we doing to make this world a better (epistemically or instrumentally) place?
Some answers to this question are already written in Bragging Threads and other places, but I think they deserve a special emphasis. I think that many smart people are focused on improving themselves, which is a good thing in a long run, but sometimes the world needs some help right now. (Also, there is the failure mode of learning a lot about something, and then actually not applying that knowledge in real life.) Becoming stronger so you can create more good in the future is about the good you will create in the future; but what good are you creating right now?
Rules:
Top-level comments are the things you are doing right now (not merely planning to do once) to improve the world... or a part of the world... or your neighborhood... or simply any small part of the world other than only yourself.
Meta debates go under the "META" comment.