In conjunction with some of my musical goals, I've been taking classes at the Passim Cultural Center in Cambridge, MA. These classes are great for improving one's playing. At $132 for 6 weeks, they're quite a bit cheaper than private lessons, and I actually find the group atmosphere motivates me to practice more between lessons so I don't fall behind my classmates. Especially interesting are the ensemble classes, which throws you in a room with strangers and lets you experience being in a band, picking, learning, arranging, and playing tunes.
If you're interested in learning music or improving your current skills, you should check it out. Find out more information here.