I also know a number of guys that make acceptable money teaching chess at private schools, homeschool groups, etc.
Another friend does something similar teach biology to groups. He also does guided walks and field trips for groups at local parks. He has a collection of interesting animals and even does birthday parties on the weekends. I also know a guy that's an animal trainer that now makes all his income from school events and birthday parties.
Or you should read about The Great Zucchini, a birthday party clown making $300 a party. I'm sure the business has gone downhill since 2006, but it's still good money for a flexible, weekend-only job.