Gregg Gillis has finally left his day job. Until recently, Gillis was doing the 9-to-5 life as a biomedical engineer, working in the experimental division doing who knows what kind of testing on what kinds of products. While the specifics of his former job are a mystery to his fans, his coworkers were left even more in the dark.

When he wasn’t at the office, Gillis was off flying around the country, playing music for big dance parties and then returning back to his mystery work on Monday mornings. He was living two lives, both opposite of the other — until recently, anyway.

Meet Girl Talk. Gillis makes it well known that he is not a disc jockey. “I’m not a DJ, because I don’t know how to beat-match records and never play other people’s songs unaltered,” Gillis says. “… I don’t know what a mashup artist is, so I could be that.”

A mashup is usually defined as a song that contains elements of two or more original songs, “mashed up.” This doesn’t really fit Girl Talk either, however, as Gillis’ tracks generally contain samples of at least 10 songs, and he uses his own production in the mix as well. No matter what you call him, one thing is for certain: the dude brings a party.

At Girl Talk shows, Gillis generally stands on a stage at a table with his laptop. He drops samples on a timeline while gyrating to the beat, taking pieces of current Top 40 and hip-hop tracks, favorites from the ’80s and then a bass line from the Beatles, for example, and just about anything that complements the groove. By the time he has his clothes off (for which he is well known), craziness has ensued and the stage is filled with people dancing around him. It’s the biggest dancing frenzy imaginable, all centered around a man and his laptop.

Performing on the same bill are Indy’s We Are Hex (formerly Ari.Ari.) — also known for excessive energy, Those Young Lions and the Peggy Sues. Talk about a big party.