You've probably heard about this guy: There's a Korean student, about 19 years old, who's suffering from lymphoma, a kind of blood cancer. There's a page for him on Facebook. Basically, he has B- blood, which is extremely rare in Korea, and also a bad blood type to get sick with, because it can only receive from O- (in certain cases) and other B- types. There's been a push to get some help for him, and because so few Koreans have B- blood, word has been circulating among the expat community.
If you want to donate blood, here's the nitty gritty:
1. You need to have an Alien Registration Card. Bring it, and be ready to present it.