If one of your family members is associated with the University, you can purchase a guess pass for $10 per day: http://www.recsports.umich.edu/members/FAQ.html
If you're willing to widen your search to Ypsilanti (which is right next to Ann Arbor), you can find a Powerhouse Gym (and a Bally's, I guess.........).
I found another place that seems to be associated with the University of Michigan that sells day passes: the MFit Fitness Center: http://hr.umich.edu/mhealthy/program...esscenter.html
Here's what they have to say!
Ugh. Sounds like the anti-black iron gym (white iron?).Originally Posted by MFit Fitness Center
Sorry, I wish I could be more helpful.............I lived in Ann Arbor for several years as a student, but even if I hadn't been a physically lazy sack of shit back then, I would've just used the U of M athletic center. (Still kicking myself for that...........I just imagine what four years of heavy lifting in conjunction with the high calorie diet my younger self was already eating would've done for me............)