You've got to respect the American Red Cross: they're just a bunch of people who love to help people. As a recipient of their assistance through multiple emergencies (hey forest fires, you suck) I've been delighted to see their various disaster apps pop up on the Play Store. But their latest tops them all: Team Read Cross gives you a ton of information on volunteer opportunities in your area, then "gamifies" the act of completing them, sort of like a Foursquare that actually encourages you to do meaningful stuff.
Sign in to the app with your Facebook account or a separate Red Cross account, and it will let you know about opportunities in your area. (Everyone gets the standard donate blood, donate money, and campaign "missions" - your mileage will vary for other tasks.) Complete them, and you get video game-style achievements. There's a huge social component as well, letting you share your activities on social networks and recruit other "heroes" to your cause. It's a bit cheesy and very self-congratulatory, but hey, it's all for the best.
One of the really stunning things about the app is how well it conforms to Holo standards. Paginated activities, a full "hamburger" side menu, easy navigation - we'd never have expected this kind of thing based on the previous utilitarian Red Cross apps. There's at least one fly in the ointment at the moment: some early users are reporting frequent crashes, which I haven't experienced so far. Here's hoping this can be fixed soon in this otherwise excellent app.