Creators of BBC Microcomputer gather (UK)

Found that the Science lab had a number of ZX81s and ZX Spectrums (including lots of Issue 1 16K Spectrums with the internal 32K RAM pack), ZX Printers (plus large box of printer paper at least 80 rolls), Tracer hardware, tapedecks, I/O port hardware, a little turtle robot, managed to persuade the science teacher to forget they were there (mainly as it hadn't been used for 5 years and this was 1989). Also found a Sinclair MK-14 in a back room in the electronics lab, I 'moved' it to see if they noticed then it moved elsewhere.

Worst thing I done in school, was on the RM Nimbus, go into a hated (mainly as he claimed to carry a knife, go clubbing, have constant sex, knife people, etc) classmate's user area and write the follow Autoexec.bat file.

@ECHO OFF
KILLBRK
BREAK OFF
ECHO FATAL ERROR
ECHO.
ECHO DIVIDE BY ZERO ERROR F01D:1075
ECHO.
ECHO PRESS ANY KEY TO REBOOT SYSTEM
PAUSE
REBOOT

(REBOOT was a simple 20 byte .COM file to do a cold reboot and KILLBRK stopped CTRL-BREAK and CTRL-C)
Took the teacher 3 lessons to sort it out. Luckily everyone we knew was in on the joke.