I used this technique in my previous workplace:
subscribe to TMOBIL unlimited tzzone (9 bux a month on tmobile cellphone). Then use a mini laptop/pda wiht bluetooth to connect to your cellphone and Voila!
Orrrrrrrrrrrrrrrrrrrr you could just do some work......
Orrrrrrrrrrrrrrrrrrrrr setup your computer to use a dialup internet account and disconnect from the LAN.... and run spy software and install a firewall... and look over your should I think I see a camera in your cieling..... ahhhhhhhhhhhhhhhhhhhhhhhhh