This list comes entirely from The Princeton Review of the most marijuana-friendly college campuses in 2015. Over 130,000 students through 379 schools were surveyed for these results. The students of the University of California at Santa Cruz host a pot-smoking event on 4/20. Generally, several thousand students show up to the event and smoke up. The state of California allows the possession of weed, but several students are arrested each year for having more than an ounce of marijuana in their possession.