If you're heading to the Tucson Gem and Mineral Show at any point, you might consider stopping at Mercado San Agustin for a bite or three. The market has MaFooCo, Animal Farm, Guero Loco's Bubba-Que and Cyclopsicle and other food trucks down there on a roatating basis to serve the nearby gem-show crowd.
In other food news at the market, the cool little outfit Sonoran Sno Cones has added a juice bar at the request of those who wanted more healthy things to eat, and a nice cup of fresh juice is a great way to kick off any day. If you're headed down to the gem show early, you might consider having a breakfast burrito at Taqueria El Pueblito, too. It opens at 7 a.m. and the burritos are big and tasty.