Something very useful that I've been able to work with here at ghost are render farms. All my past work has been done on a single computer with a single processor, so rendering had to be done overnight and sometimes for several days. A render farm is essentially a giant room full of processors, since rendering is so intensive and can take days for a scene, the more processors, the faster everything gets done. The main farm they have is a collection of 16 processors hooked up in a room. The funny thing is we just got in a dual quad-core mac (yup, 8 processors), which by itself is as fast as the entire farm. If I do more contract work for smaller companies I'm going to need to build a small cheap farm myself and using ghost's has taught me some valuable lessons and problems to avoid. We had a lot of problems with different renderers on the farm, especially mental ray. My biggest lesson was to never build a farm mixing PC and MAC processors. It's only asking for trouble. Macs and PCs have slightly different byte orders, naming conventions, and ways of processing information. Since I've always worked on P's and the software availability is far superior, I'm going to be sticking with PCs.
Since I always attach an image, here's a picture of a server farm, weeee.