Hey man, my school uses RM systems too. They're bolted down pretty tightly; I've tried most of the tips and tricks but they've all been blocked. I haven't tried the Windows key + r trick though.. the Windows key is blocked but would the same effect be achieved via Pressing ctrl + esc + r?
If so, that little proggy sounds like a fun one to try
I'm in my last year so I spoke with a few friends about setting up a few little pranks and I'd set my mind on one involving the school comps. A friend told me a while back about a key combination you press during boot to bring up a network menu or something.. if anyone could shed anymore light on that I'd appreciate it.