Do you have a killer app? That is, something that you absolutely positively have to have that they can't say no to? It's going to take something along those lines to get access... most colleges are very wary of letting students loose on their servers, especially with something as potentially risky as CGI. There's a ton of things they could do to compartmentalize your access and limit the damage you could (accidentally) do, but you need to come up with some compelling reason why they should bother. "Just for fun" will not cut it.
Alternatively, find a champion. Instead of appealing directly to the Web Gods find an administrator or teacher that's willing to go to bat for you. You are insignificant and easy to say "no" to. A tenured full-professor is much harder for them to ignore. :-)