I use Seti at Home as screensaver, that helps us protect our Earth of asteroids and mini planets.
http://setiathome.ssl.berkeley.edu/download.html

You can download and watch how it analyzes the data. Very exciting.

You can even find an asteroid and give name to it! [Linked Image]

The sw does no harm on the pc, runs when screensaver is active only.

You may setup the connection, for you can choose to be alerted when the sw needs to contact and send info, or it can do it automaticaly.

The world is full of beauty if the heart is full of love