If you're looking to do things a bit more casually, or might have a business meeting there are a number of community centers around the Lake. These are usually very affordable and are really great for meetings. Pricing is usually exceptional as well. Here are a few to consider:
Bachelor Valley Grange. 9355 Government Street, Upper Lake. (707) 275-2661
Clearlake Community Center. 3245 Bowers Ave, Clearlake. (707) 994-8201 x100.