You can participate in running simulations of high-energy particle physics (Large Hadron Collider)
The LHC@home 2.0 project Test4Theory allows users to participate in running simulations of high-energy particle physics using their home computers.
The results are submitted to a database which is used as a common resource by both experimental and theoretical scientists working on the Large Hadron Collider at CERN.
Lots of volunteers around the world are connected to Test4Theory right now. See where they are (map coordinates are randomized at city level for privacy; undetermined locations are shown in the Bermuda triangle). Or check the current list of top contributors at the T4T Leaderboard.
Hopefully, these explanations can help give an idea of why the computing resources made available by volunteers in this way can be crucial for improving our understanding of what is really happening inside the beam pipe of the Large Hadron Collider.
Therefore, if you like the project and want to collaborate:
http://lhcathome.web.cern.ch/test4theory
Cool!