cool party lights

Ever wonder where those corporate Christmas party djs get their cool light show equipment? You know that lights that they've got going on that are almost mesmerizing to look at.(Maybe that's why they use them!) Of course you already know that you're probably not going to find something as specialized at your local hardware store. But I don't know the hardware store where you live.
Chances are though, you're best bet for finding something like that is online at a store that specializes in such products. Why waste time and money looking anywhere else?