Help look for extraterrestrial life with your computer! I've been thinking about making a RallyPoint group for this on there.
What is it? When you are not using your computer (when you're asleep or away) UC Berkeley will use your computing power to help sort through signals received at the Arecibo Observatory.
What's in it for you? Your name will be on every piece of data sent to UC Berkeley and if your machine (computer) finds extraterrestrial life, your name will be on the Nobel Peace Prize
Is this safe? Yes, if you still want to participate, but don't like the fact of allowing an outside source accessing your hardware, I'm going to start making Raspberry Pi machines to run 24/7 and will have 0 access to my computer. Also, you can also run a virtual machine. While that is not fool proof, it can still be a security barrier.
Can I do other things besides look for aliens? Yes, a full list of programs you can donate your computing power to is here (
http://boinc.berkeley.edu/projects.php)