Is it possible to use just a part of the CPU of the slaves?

[Miguel Hatrick]

I'm thinking about making a cluster with all the computers of the campus but i'm wondering if it's possible to configure it to either use them when they are idle or to just use a part of the CPU power of the slaves. Could anyone give a hint? or perhaps tell me where to look for information?
Any help will be Welcome!
Thanks!
Miguel Hatrick