PHILTONCRUNCH060107_01.jpgPHILTONCRUNCH060107_06.jpgParis Hilton PHILTONCRUNCH060107_03.jpgWell, exercising does produce endorphins, and endorphins make you happy, so perhaps that's why former socialite/present inmate Paris Hilton has that ecstatic expression on her face after leaving the gym just a day or so prior to entering the big house.