If you want to help cure things like cancer, diabetes, Parkinsons or similar things there's no cure for, you can help. Using something like SETI@home, you download a small program and it uses your idle computer processing power to work out a load of calculations and sends them back to the Internet.
Read more about the project at this site: http://www.intel.com/cure/.
To view or join the team, visit the team page.
If you have any questions, I'd be happy to help ...