Colima and Comala are two small towns worth exploring. Just be sure to go with a reputable tour guide.

Colima is the capital of the state of Colima. There are several museums and shopping. Like many Mexican towns/cities there is a nice central square with fountains and flowers. Surrounding the central square is a museum, the governors palace, and a large cathedral. Also, just outside of Colima are the ruins of La Campana, which are located near two active volcanoes. The ruins at La Campana were discovered in 1995 when a team of construction workers started digging the foundation for a new shopping mall. To date only about 40 percent of the archeological site has been uncovered. There are about 12 different structures (so far), including several Meso-american/pre-Columbian pyramids from about 500 AD.

The "Pueblo Magico" (magic village) of Comala is a small town with lots of Spanish colonial charm. The Mexican board of tourism has given 33 small towns the designation of "magic village" - they are unspoiled towns with cobblestone streets and colonial architecture. In Comala you can also tour a coffee processing plant and buy some fresh coffee.  

Don't miss Comala for brunch/lunch. There are several 'botaneros' there that are geared to families, unlike most botaneros in Mexico. For the price of beverages, even soft drinks, a friendly waitstaff will bring you plate after plate of antojitos (snacks) such as enchiladas, riblets, slices of pork loin, sopes, etc. The food is wonderful and you can't beat the price. As long as you're drinking, they'll keep bringing different small plates of snacks. Wonderful!