EXCLUSIVE: The marijuana legalization movement gained major momentum in the recent November elections as measures to regulate the drug made it to the ballot in three Western states and passed in two — Colorado and Washington — with several others working on similar legislation. Now the grass-roots campaign will serve as the backdrop for a comedy in development at Fox. The Happy Tree, from former Entourage executive producers Rob Weiss, Mark Wahlberg and Steve Levinson, centers on a brilliant young corporate attorney who, after a nervous breakdown, quits his job and seeks a life of peace and serenity on Venice Beach only to find himself the unlikely voice for the marijuana “legalize it” movement. The project will be produced by 20th Century Fox TV and stems from Weiss’ blind script deal there. He will co-write the script with Jay Leggett and Blake Leibel, who co-executive produce with Lawrence Longo. In addition to Entourage, Weiss, Wahlberg and Levinson also executive produced together another HBO series from actor-producer Wahlberg’s Closest to the Hole and Levinson’s Leverage banners: How To Make It In America. Weiss, repped by UTA and Hansen Jacobson, is currently working with Wahlberg on the feature The Switch for Universal. Leggett is repped by Liberman Zerman Management; Leibel by WME and attorney Sean Marks; Longo by Marks; Wahlberg and Levinson by WME and Sloane Offer.