What can I do with garbanzo bean flour?

You can make vegetarian meatballs. http://myerecipecorner.blogspot.com/2011/02/pakoda-kurmapakora-korma-chickpea-flour.html

Definitely socca. Add some cumin to the batter if it isn't already in the recipe.

I like the socca suggestion.

You can add moderate quantities to baking, no more than 1 part in four, especially when soy flour is called for (as a substitute). Gluten free bakers often use it as part of a grain and starch mix to replace wheat flour.

we made these and absolutely LOVED them:

http://www.food52.com/recipes/4406_artichoke_fritters

Many Indian dishes, especially fritters and appetisers, use chick pea flour.

Socca/Farinata

Crespelle.