If you type in "Game Grumps" at the Museum Entrance, secret text will appear saying:

"Far behind the inventor you see a poster for Game Grumps, the popular internet series hosted by Arin Hanson and Dan Avidan. The poster is bright orange with text in BD Cartoon Shout font, and it features caricatures of the show's hosts sporting grump expressions.

[Note: This Easter Egg is brought to you by Vitas Varnas without the knowledge or participation of the Game Grumps, members of their families, deceased relatives, or people they hang out with in pubs.]"

This is a reference to the internet let's play channel Game Grumps and their logo which uses the font style mentioned above. Actor Vitas Varnas was also the one who had inserted the Easter Egg into the game, who has often contributed games to the show.
Contributed by KnowledgeBase