Simple Windows batch file to annoy your friends/enemies. It loops infinitely, echoing the ASCII bell character and waiting a random amount of time before continuing.
Works best on Windows 7 & 8. Requires line 3 to be replaced with this:
set /A rand=%RANDOM% %%10000
and line 5 to be replaced with:
ping 1.1.1.1 -n 1 -w %rand% > nul
to work on earlier versions. This change also trades maximum length for finer control.