Zoom BFX-708 Bass Effects Processor w/PSU

Although (like most multi-FX boxes) this has a lot of features that are useless, it does have some decent amp models in it, as well as a cool little rhythm machine and looper that set it apart from a lot of other pedals in this style/class. Throw in a tuner feature and some fun effects, and this is actually a pretty neat little pedal to run your bass through (or some other instrument, if you're feeling experimental).

A quick google search for Zoom BFX-708 will take you to the manual, which gives a full feature run down.