A trick I've learned (thank you Thomasina) for jam sessions when I'm playing mountain dulcimer and don't know the tune is to flip my dulcimer over on my lap and -- gently -- use it as a drum. This allows me to play in the jam and add a new sound to the mix. For me, it only really works with faster tunes. I've never used this when playing guitar, but I'm sure one could.

- Sean