I'm past the point of wanting to take real college courses. But I've been attending a program called "Elder Education Enrichment" for a year or so now. (I call it "old farts school"). It's a one hour lecture on Monday and Friday afternoons, generally taught by a college professor. They break them down into series of anywhere from 3 - 6 weeks with a common theme (food, Islam, the former Soviet Republics, the Medieval Era, etc.). Some series have the same lecturer for the whole time; others have a different lecturer each week, but sticking to the common theme. They charge $5 a lecture or $40 for the whole "term". You get to hear some great lectures and engage in a really good Q&A afterwards. No homework; no term papers; no attendance taken.
Many of the college profs have commented that they love doing these lectures because everyone is attentive, they don't wear backwards baseball hats and they ask really good questions.