Diane Keaton munches "special" brownies as the cancer-stricken family matriarch, and Sarah Jessica Parker plays the uptight Meredith, whose freak flag flies under the tutelage of her fiancé's brother Ben Stone (Been Stoned?), played by Luke Wilson.
2. The Night Before (2015) written by Jonathan Levine (The Wackness) and starring Seth Rogen and Joseph Gordon-Levitt, features Dickensian pot dealer Mr. Green (Michael Shannon) manifesting marijuana's three vision quest abilities: to put you squarely in the present, to illuminate a future you fear, and to come to grips with a past you have buried. To the character who protests paranoia, Mr. Green replies, "Sometimes it's good to be uncomfortable." Packed with the usual party boy inanities, this one at least has cameos from Mindy Kaling and Ilana Glazer (Broad City) as Scrooge.
Bill Murray finds his soul with the help of his pot-puffing girlfriend, played by Karen Allen.
4. To deal with his sudden change in fortune, Eddie Murphy jumps into the john to take a toke, and Dan Aykroyd lights up a spliff in disguise as a Jamaican in Trading Places (1983), set at Christmastime.
5. In The Man Who Came to Dinner (1941), the unwanted visitor's host is based on H.H. Timken, the Ohio industrialist who planned to bankroll hemp production in the US. Absinthe is mentioned.
6. In the 1951 movie The Lemon Drop Kid, Bob Hope sniffs Santa's pipe and acts high while introducing the song "Silver Bells":
7. In Four Christmases (2008) where the always hilarious Vince Vaughn and Reese Witherspoon attempt to dodge their wacky relatives, Sissy Spacek warns her grandson against grandma's "special" brownies.
8. A Very Harold & Kumar 3-D Christmas (2011) must be mentioned. Best moment: when Danneel Harris (Vanessa) convinces Kumar not to stop smoking.
10. A tie between the 2008 ER episode, "The High Holiday," which features Charlotte Rea (who played the housemother TV’s staid sitcom "The Facts of Life") accidentally dosing the staff at their Christmas party with her pot brownies, made for a friend in chemotherapy. And the 2009 Friends episode in which Monica is baking Christmas cookies, and Phoebe comments, "A plate of brownies once told me a limerick." "Were those funny brownies?" she is asked. "Not especially," is her response, "but you know what, I think they had pot in them."
And for you kids in town without a Christmas tree, the "smoke your marijuanaka" line in Adam Sandler's original Hanukkah Song always gets a big ovation whenever he performs it live. His newest version #4 of the song shows he's still smokin:
UPDATE 12/2019: In 2020 look for "High Holiday," the plot of which is (according to IMDB): "In order to lighten up her uptight family, the free-spirited daughter of a conservative politician brings weed-infused salad dressing to Christmas Eve dinner. With Tom Arnold, Jennifer Tilly, Cloris Leachman and Shannyn Sossamon.