Uses for a Mac network

I wanna find a reason/use to support the building of a Mac network, I thought of a render farm but not sure how useful that would be off-site from a customer's office. Is there any other new or popular usage for say 5-10 souped up Mac Pros? I'd really like to find a use to build a big Mac Network.

Thanks

You have 5 to 10 of them and you don't know what to do with them?

LOL, no I want an excuse to purchase 5-10 and link them together. I'm racking my brain for a use for 5-10 MAC Pros.

Well, I have one. I can't find a use to own a second computer at all.
I had it encoding a video while I listened to music, surfed online, and burned two DVD's. I don't know what you could really do with more than one.

Edit:
I failed to mention it was still screaming for more. It still wasn't slowing down or anything. I was doing this on the quad 2.66GHz model.

I'm thinking rendering is about it for needing more then one.

rendering what?

Video with maya

Get a cluster node if you want to crunch.