My message to every single computer in our HS:
"Hey what's up!"
my friend added to this:
"Your network (H:/) drive is being deleted."
School administrators and teachers did not find this funny.
He was on phones, got about twenty calls including one from a VP - with even more popping in throughout the following week as people returned to workstations to see the dialog. We were able to play it off as "testing the network" (not wrong I suppose), but our manager was a responsible sort and had it blocked with a group policy shortly after.
Ha, yeah I got banned for using net send as an IM app with friends too. There were a couple of us in my school who were skilled, enthusiastic programmers - it is kinda stupid that the punishment they decided on was to prevent us from being educated :-/
I changed the homepage to a webpage which redirected to file://c:/con/con (which for those who don't know caused a windows BSOD at the time).
IT teacher thought it was hilarious, used it as part of the lesson about how computers can be broken into, and told everyone "ok we've seen that, don't do it again".
Another time I remember writing a simple program, probably in qbasic, which captured passwords to a file. It only wrote a the first 4 or so letters to the file - showed what we could do, had a little fun, tricked the teacher into logging in, and then told him "ha ha".
As long as you came up with creative things (not just copying others, which is tedious), which didn't cause too much disruption (no deleting files), and stopped doing it once you proved it could be done, you were fine.
Networked IT was new and exciting then though, to the students and the teachers. A few years earlier and it was all BBC Micros, a few years later and everyone was on the internet and trying to install backorifice, but for a brief moment well meaning harmless (for a teenager) curiosity was rewarded.
*HELP. on a BBC Master
Those folks came to me with a request for some sort of Net Send revenge.
I wrote a VB script which ran in a loop, which randomly 8-10 times a day would get a new message from the BOFH excuse generator and net send it.
Ahh, youth.