I've often been asked how I find so many classes/workshops to go to. It's all in learning where to look and remembering to check back with places that have offered classes in the past.
For example... if you are interested in gardening of any sort the first place to look for workshops is at your local Agricultural Extension office and with the local Master Gardeners group. Both can be found by a web search. Then look over the sites to see if they offer classes. An email or call would be a good idea too.
That is exactly how I came upon a multi class gardening clinic we went to last Saturday. For $10 you got lectures in lasagna gardening, water gardening, 2 liter gardening, irrigation, herbs, and blueberries. Plus some freebies and lunch. Not bad.
Other places to look are in your local newspaper's community section, at local museums, the bulletin board at specialty grocery stores, and at all hobby type stores. Facebook will often 'pop up' local events. Even if you're not interested in the particular one, you can use it as a jumping off point to find others. There's usually a "see similar events" (or some such wording) that you can click on.
With just a little looking around, you can find so much to do!