School Tries to Squash 4/20 Bash With Stinky Fertilizer 10K flocked to University of Colorado-Boulder last year By Matt Cantor, Newser User Posted Apr 20, 2012 9:59 AM CDT 41 comments Comments A judge says the University of Colorado can bar visitors for a day. (?miss.libertine) (Newser) – Last year, 10,000 people showed up for a giant marijuana rally at the University of Colorado-Boulder—and school officials don't want it to happen again. They got a helping hand from a judge yesterday, who supported the university's plan to bar outsiders from its campus today—4/20, a hallowed day for pot smokers. The school has tried—and failed—to stop revelers in the past; previous efforts have included switching on lawn sprinklers and offering cash to any student who would identify people caught smoking in photos. This year, not even students will be allowed to enter Norlin Quadrangle, which has played host to the event in the past. And officials took things a step further, blanketing the quad with a smelly, fish-based fertilizer, reports the AP. They're also offering a free Wyclef Jean concert timed to coincide with the traditional 4:20pm pot gathering. But campus groups are still planning events, Colorado Daily reports. A lawyer for local medical marijuana businesses says the rally offered an "anti-Prohibition message": "If free speech isn't allowed on a college campus, where is it safe?"