In addition to micro chipping your pets in May, (details follow) you can enjoy Medella Vina ranch's Third Sunday of the month Farmers Market and Artisan Fair which occurs 8am to 2pm (includes food trucks).
Microchips are $10 per cat or dog for Pima County resident pets. No appointment necessary and no limit to number of pets. Dogs must be on leash and cats in carriers.
Microchip registration is included and is free for life, including updates, thanks to Foundanimals.org registry. It is recommended that pets be vaccinated prior to taking to public gatherings.