You know that stupid chain letter that says Bill Gates will give money to each person you e-mail? Well it's a lie. But this is the truth:
Microsoft is donating money to charity for your instant messages as part of their I'M initiative. Put the tag for your charity of choice in your nickname field, and Microsoft will donate money to that charity for each of your instant messages. You need to be on Windows Live Messenger 8.1 to do this, but it's an easy (and free!) to way to help out a worthy charity, and they have several to choose from.
The badge in the upper right corner of this blog will take you there, as well as tell you who I'm currently donating to.