Everyone knows about the Red Cross and their humanitarian efforts and I'm pretty sure you've seen their ads all over the place. Such as this one:
Creative, humorous, sticks in your head, makes me want to donate blood, perfect.
I'm also quite certain that everyone is aware of the disaster that struck Japan recently. This ad by Red Cross is unique in that you can use your Smartphone to donate money directly to the cause.
And if you haven't donated yet, you should. Even if you're a poor, starving University student (like me) every little bit helps.