If you're like me and you like to have a post-race / pre-flight shower --
This place is open on Sundays (unlike most of the other Phoenix-area rec centers I checked), and an adult, non-resident day pass is $6.75. It's on the way from the Sunday event to the Phoenix airport.
Freestone Recreation Center
1141 E Guadalupe Rd, Gilbert AZ
* Open Sundays 10am to 5pm.
* Bring your own towel.