Ashlee Simpson went wild at a Hennessy party last night -- someone had too much punch!

TMZ cameras caught Simpson starting a mosh pit at the Hennessy Artistry Finale on the Paramount lot in L.A., shoving her girlfriends while her boyfriend's band, Fall Out Boy, rocked out on stage.

Simpson showed off some of the goofiest moves this side of Bai Ling at the party, and did her best to keep the crowd rowdy for her man's performance.