I caused havoc in high-school with that. And finding a way of executing binaries inside Novell's Netware thing, via the "Open" dialog within any Office application's Visual Basic macro editor haha
That's how we ended up with 8-player age of empires 2 deathmatches after hours ;)
However it turned out that you could rename them .bat or .cmd and they would execute just fine.
I think Doom 2 multiplayer was extra fun because of the added need to be aware not just of in-game enemies but also the need to be aware of the teacher and be ready to instantly quit at any moment.
Wrote a batch script that used a wildcard - it took them a while to find it and I was very lucky the only 3 persons who knew who it was wouldn't tell anyone. One was a teacher and I am thankful until today that he didn't screw up my life with telling this.