Up in Smoke (1978)

Synopsis
Then professional potheads Cheech Marin and Tommy Chong teamed up for Cheech & Chong: Up In Smoke, which features the drug-addled duo on a road trip throughout California; that is to say, a road-trip they hope will culminate in finding some quality weed. Instead, a series of mishaps result in their respective deportations to Mexico. Desperate to get back to the states so they can perform in their band's gig later that night, Cheech and Chong unwittingly agree to drive a very unique car across the border -- rather than steel and various metal bits, the vehicle is constructed entirely out of marijuana. Back in the States and accompanied by two extraordinarily out-of-it female hitchhikers, the stoned group meanders about in an attempt to get their musical performance together, and narrowly escapes from local law enforcement agencies on numerous occasions despite their complete inability to realize they were being tailed to begin with. The incredibly low-budget movie surprised critics, grossed millions, spawned a series of lesser follow-up films, and cemented Cheech & Chong's cult-status among potheads across the globe. ~ Tracie Cooper, All Movie Guide