Gutmonkey: that deep-seated desire/obsession/passion/addiction that, gut-level, inspires you to act.
From "gut" and "monkey on your back." Not a derogatory term, but rather one that invokes the passion of an addiction and the gut-level inspiration that moves people to action.
The word CafePress made up to describe the passion/obsession/desire that leads its users to create or buy specific merchandise that relates to their own gutmonkey.
Sam's more than just a foodie; trying new restaurants is a serious gutmonkey for her.