I really never have known how to do all the network tricks and stuff, like shutting down someone else's system through the Command Prompt. A lot of people had done the thing where you hit Ctrl + up or down to flip the screen, I never really had known how to do that either. Probably better I don't know a lot of that stuff, I'm not one that likes to get in trouble. As for OC'ing a CPU on those systems, most schools probably have prebuilts which have the BIOS locked anyway. My school gets only HPs now w/ AMDs. The last Intels that they got were P4's. Then they went AMD 64 for a year and now they have X2 2GHz CPUs as the best systems. My school gets new systems every year, but not for every place. They replace them a little at a time. They may just replace several computer labs one year, or teachers old systems. This year the library got some AMD X2s.
For the wireless question, if you are at school, chances are you aren't going to get anyone else's signal anyway. Probably too far away from anything. If you did pick up an unprotected signal you should be able to connect though. I keep my wireless signal unprotected because we're in the middle of nowhere anyway. No one else even on the road can pick it up.
People at my school at least in one class just got to all the unblocked flash game sites. If one gets blocked they all move to another one. Right now half the class plays a stupid helicopter game. One guy in there seems like he would die if he doesn't get his daily dose of flash games... I got a copy of AOE2 on my flash drive I copied from the student public drive. That's better than flash games. If there's nothing to do I'll just play that.