The Tucson Tango Calendar is a good source for most of the scheduled tango classes, practica and milongas in Tucson.
Learn-To-Tango provides and organizes the majority of tango events in Tucson. It is run by Rusty Cline and Joanne Canalli.
Many of us attend their milongas and practica. A number of us take classes taught by Rusty.
Green Valley Argentine Tango is an active club in south Tucson. We have attended many of their events.