The most secretive body parts are muscles, which hide behind layers of skin and appear only occasionally to help lift cars off trapped kittens. Flex your biceps in the absence of a cat emergency with today’s Groupon: for $30, you get a 30-day membership package to In-Shape Health Clubs (a $388.98 value). The package includes:

• One-Month of club access for you and up to 3 family members for a single, couple or family membership
• One month of dues for Platinum Plus membership
• One month of unlimited tanning
• Enrollment fees
• Membership card fee
• Unlimited towel service<p>

This Groupon expires on November 31, 2011 and is valid at all five Modesto locations: 1234 McHenry Avenue (open 24 hours), 2700 McHenry Avenue, Floyd Avenue, Pelandale Avenue, and Prescott Road.

Founded in 1981 with the simple purpose of helping its patrons stay healthy, In-Shape Health Clubs now have 49 locations peppered across California. All of the Modesto satellites host muscle-molding free weights as well as a cardio theater, which occupies minds with overhead televisions or live puppet adaptations of Carmen as bodies exercise atop modern machinery. Locations may also offer such amenities as indoor pools, children’s activities, rock-climbing walls, racquetball, and group exercise classes such as cycling, Zumba, and yoga; check each location’s website for a full list of amenities. As toned physiques emerge, unlimited on-site tanning can accentuate bodily peaks, valleys, and subducting tectonic plates with a hint of bronze.

After a month of visits, Groupon holders may be subject to the enrollment and processing fees included in this deal.