I go to a non-profit Ballroom Club. Really cheap classes, too. You don’t need a partner, we have a couple people who showed up alone. I think some of the Ballroom Club members come to hang out at the dance hall, and if there’s an odd number of people class they’ll join in to even it out.

Look in the phonebook under dance, or do a google search. Check your local university to see if they offer it too (mine offers ballroom, but not swing), universities often have better deals than other places in town.