Stealth Hippie
A person who is interested in typical hippie endeavors (such as following jam bands across the country) but who does not display the typical hippie characteristics (instead he has short hair, holds down a regular job, car is not covered in stickers, does not wear hemp necklaces, bathes) with the result that people who interact with the stealth hippie on a day-to-day basis (bosses, coworkers, neighbors) are unaware of his extracurricular interests.
Oh I know, he's a stealth hippie. He's seen like 150 shows and sells hetty crystals in the lot.