At the XO Lounge in downtown Washington one January night, people who paid a $10 cover charge were greeted with samples of caramel popcorn, brownies and crisped-rice treats — all infused with marijuana.

Customers could browse three floors with tables featuring all manner of cannabis: edible candies, smokable flowers, wax, oils and more. All were available only after a suitable “donation” was given for a sticker, or a football card, for which the cannabis was billed as simply an added “gift.” The top floor featured a ­full-service bar, and music thumped throughout as a steady flow of customers entered the restaurant and nightclub. Read More…