You can: go spelunking Ursula Watson, The Detroit News
Find a cave and go spelunking. Also known as "caving," the object of this exercise is simple -- check out a cave.
While Michigan is not known as the Land of Caves, there is one to explore; but it is a bit of trek, which, of course, is half the fun. The 50-foot-long Bear Cave in Buchanan (in the southwest part of the state) is made up of a variety of ores and stalactites.