are you looking for premade loops, or to play around with software samplers/synthesizers?
there is this awesome freeware program that i use called buzz,
www.buzzmachines.com, totally no spyware or anything. don't let the interface intimidate you it is actually really intuitive - every function is right there and can be easily automated and all the signal routing is really easy too. it is just mostly text-based for the seqeucning so a lot of people don't get it... but if u give it a chance and like it, it is super rad. it also has really good support for VST instruments.
it is a little buggy but if you are interested send me PM an I will send u some good links on it, and the forum at the site I just linked u to is a really good resource.