Our local community college offers classes for those 55 and over and they cost $20 to register and then you can take any of the classes you want. They are taught by volunteers and they had some interesting ones.
For those over 65, they can take any of the regular college classes for a single registration fee of $25. You don't get credit but it's a great way to keep your brain active and meet some new people.
I'm signing up in January but haven't decided which class to take yet.
