Awesome!!! It's great that this takes you out of your comfort zone. Experiences like this help take your playing to a new level.

All great advice here...I would add one more thing: be sure to listen, actively listen, to what the other musicians are playing. Try to make what you play fit in with the music the other are playing. Let yourself go and get lost in the music and the groove. It can be a very surreal experience...let it happen. It's more about playing in the groove than showing off technique or musical knowledge.

I would also suggest recording it...but be sure to ask the others if it's ok.

Just remember it's about fun. You are not auditioning...you are jamming!

Let us know how it goes!