Here's our idea: gather together all your friends and invite a few who have an instrument (hopefully portable ones—have the friend with the piano host this shindig) and plan a night of frivolity that's totally in tune with the environment.
Guitars are a popular jam session tool; grab a couple of acoustic axes and sit around a fire pit in the back yard, or around a table on the patio. Make sure there's plenty of drinks and food to go around, and then, as they say, "let the music take control...."
Ok, so maybe jam sessions happen a little more organically than that. But try inviting a few bandmates over to your next party, and watch as an evening unfolds, without the need to plug anything in.
For more, check out our roundup of the Best Eco-Friendly Entertaining Ideas.