Donate Blood-It's a Mitzvah!
So there was a blood drive at our very own Santa Cruz Hillel (located next to the 7-11 at the base of campus) and it was pretty successful. Since one person who donates the standard amount of blood can save, on average, 3 people's lives, and judging by the turn out, I'd say it was really amazing. Big Yasher Koach to Monica and Ayla and everyone else from Hillel who helped organize it! It was put on by Stanford Medical Center (check http://bloodcenter.stanford.edu/ for more info.)
Anyway, I looked up some of the Jewish aspects to this and it turned out there is a great deal of encouragement from leading Rabbis to donate blood if one is able to. This is primarily because it is seen as Pikkuach Nefesh (saving of life) and, for the most part, healthy people who are capable face no risk that the operation will have any serious after effects. (One may be a little weary for the next few hours and a donor should not do anything too physically exerting at least for the rest of the day--also one should drink plenty of water and take in plenty of nutrients before the operation.)
Quite a bit more time has been spent ascertaining the Jewish values in donating an organ which is obviously a much larger commitment. On http://www.medethics.org.il/articles/JME/JMEB1/JMEB1.37.asp
you can see that organ donations too have been up for serious debate among Torah scholars.
For a Halachic analysis of donating a kidney and many of the leading opinions involved see: http://www.dailyhalacha.com/Display.asp?ClipDate=1/8/2007
In general, there are four fundamental issues concerning transplantation from living donors.
A. The danger to the donor.
B. Donation under coercion.
C. Sale of organs and tissues.
D. The legally incompetent donor.
All halachic authorities agree that where a procedure is not a life saving measure, one may not significantly endanger the life of a donor, nor may one coerce a potential donor to donate.
For more of a basic summary on Jewish medical ethics check: www.aish.com/societyWork/sciencenature/Why_Jewish_Medical_Ethics.asp