Sam & Max: The Devil's Playhouse
Sam & Max: The Devil's Playhouse
In Episode 4, Beyond the Alley of the Dolls, having Max use the psychic ventriloquism power on the jukebox in Stinky's Diner will have Max sing "I remember my childhood in Brighton..." before Sam stops him from singing any more of the song.

This is the opening lyric to the song "King of the Creatures" sung by the character Conroy Bumpus in LucasArts' earlier title Sam & Max: Hit the Road.
Contributed by SilverSupernova
In the cloning chamber under Stinky's Diner in the episode "Beyond the Alley of the Dolls" is a broken dispenser from Team Fortress 2. If you examine the dispenser, Sam will start hitting it with a wrench, similar to how an engineer would fix/upgrade them in Team Fortress 2, including the same sound effects.
Contributed by gamemaster1991