There's this Family Guy episode where Peter compares Lego to MegaBloks to Lois, who just doesn't seem to get it. Then, he builds a crummy rocket in a kid's room.
In a Simpsons episode, they go to a mall and eat at arts and crafts type restaurant, where there are eating utensils made out of Lego.
Also, they have Lego in a couple of Robot Chicken episodes.
They also showed a logo made out of Lego on Disney Channel
In the movie, Kickin' It Old Skool, the main character is seen playing with Lego in a bar while the confused waitress watches him.