The closing scene is a reference to a Rolling Stones magazine cover picture of John Lennon and Yoko Ono.
The character Zed the big biker guy in the jail, is clearly a reference to Black Label Society guitarist/singer Zakk Wylde. They have the exact same outfit and signature hair/beard.
References The Bad News Bears: Mia asks if they should be calling Chico's Bail Bonds. This was the sponsor of the little league team coached by Walter Matthau in the film.