A Geekbean is a tiny little creature that is a lot more wisdom-filled than most, but yet also a lot more bean shaped than most. A freaky little thing to be sure. Eeeeeeeek.
Look at that Geekbean, it is rolling down that hill at a remarkable pace. How fruity.
A bean bag die of the most awesome variety. Usually a d20 but also has been spotted as d12, d10, d8 and d4.
"That Geekbean is so awesome, I threw it at the DM when he did a TPK"