Office Wars is a web based trading game with gameplay based on DopeWars. If you were a fan of the DopeWars games then give this a shot. It doesn't have fancy graphics or any of that jazz, but it is really fun to kill a few minutes during downtime. The main objective of OfficeWars is to become to top trader of office supplies and crush your foes!
To learn how to play you can read the instructions or just create an account and start clicking around.
If you want to see how other players have done in the work-o-sphere, you can check out the High Scores List.