Dax Shepard's character is named "Crosby", which is the same name of the character he plays in "Parenthood". Both shows are produced by Jason Katims and take place near each other ("About a boy" in San Francisco and "Parenthood" across the bay in Berkeley). Add the facts that both Crosbys have an infant daughter, both are NBC shows, and Will and "Parenthood" Crosby work in the music industry, and you have a clever crossover.
The "monster" or gargoyle seen during the sleepover is actually from Lover's Vow in the Tales from the Darkside: The Movie.