Multiple computer render, node, etc farm ideas?

So i am going to be getting 9 (yes 9) 1.88ghz single core 2gb ram, 80gb hdd servers in rack mount style. Im getting these for free or dirt cheap.

So i have a few ideas of what i want to use them for, But not really how, But here are my ideas so far:

1. Web Server, but have the load balanced across the machines.

2. Server raid array, so like using multiple servers with multiple HDDs each and having them doing backups and backing each other up

3. I am going to be getting into some security research stuff and there are some scripts i want to write to calculate stuff for me, Like rainbow tables and whatnot. So i thought well with all these machines i could speed stuff up, plus get it off my main computer.

Thats all the ideas i have come up with so far, Their all things i have been wanting to do, but never got around to doing. Only problem is that i have no bloody idea how to do any of it.

I do consider myself a very techy person (more end user stuff though less corporate networking etc...) so i am willing to take up a challenge and learn something new! I am 100% open to any ideas for what to use these machines for.

It really depend on what you want to do. If you want the servers to process a lot of information faster I would consider settings up load balancing on them. How to do it will depend on what OS you decide to use. I would probably looking into Linux cluster. A lot of information is available on Google with a quick search.

also...
A web server will only need load balancing if you have a lot of traffic coming in.