One of my favorites. I worked with a group overseas who were all fans. One Major could do a perfect Lumberg while a Navy CDR did a side-splitting Milton.
We ordered the Office Space kit from ThinkGeek. It had an Initech coffee mug, a Jump to Conclusions mat, a tablet of TPS cover sheets, some flair and even a PC Loadletter sticker which we promptly affixed to our department printer.
I bought that box, too...the bag of Flair and tiny red stapler were nice additions.