Freddy Pharkas, Frontier Pharmacist
Talk to the piano player in the Golden Balls Saloon and you can select which song of the game he'll play.
Check out the little papers sticking on the wall in the general store. You'll find a whole bunch of references. There's one from King Graham from the King's Quest series (also referring to Passionate Patti from Leisure Suit Larry). There's one referring to Laura Bow 2 (Dr. Miklos' lost ferret Daisy in the Leyendecker Museum). There's a wanted note for game designer Al Lowe. There's also references to the Kung Fu series with David Carradine, "A Few Good Men" and the car "Kit" from "Knight Rider".
There is a wanted poster for Rubenito Huante in the sheriff's office, referring to the game's character designer, Ruben Huante. Sometimes it is also a poster of Mike "Stinky" Pickhinke, Q&A lead of the game.
When you recover the ladder from the ant pile, you'll see a couple of buzzards and Cedric from King's Quest 5 landing on the bridge. Try talking to him and touching him for some funny remarks from the narrator. Exit to the bridge and immediately return and the buzzards will have gotten the best of Cedric...
Use the shovel on the floorboards in the pharmacy. A monster will crawl from underneath the boards, saying "I'll swallow your soul!", to which Freddy replies "Come get some.". A reference to the Evil Dead movies with Bruce Campbell.
Press the number keys 0 to 9 for some random in-game sounds like farts and such.