I'm 54 and get together once a month at a buddy's (Drummer) house. We keep equipment there. People just need to bring instruments and/or a microphone if they sing. The three of us "Core" players started playing together in the 80's. We've remained friends through the years and jammin' allows us to get together, BS, maybe try a couple of new (to us!) songs. We have a rotation of guests sit-in which keeps things fresh. No earplugs required. No tear down, just cover up. Just FUN!
Nothing special, just something my friend tried recording one afternoon: http://www.youtube.com/watch?v=OGGBi-i-EJ0