1.In the first Toy Story, the titles of the books on the shelf are all named after Pixar shorts.
2.This one is more about the limitations of CGI in 1995, but did you notice that all of Andy's friends are also Andy?
3.Speaking of CGI, the teapot used in the tea party scene is a nod to the Utah Teapot, one of the first digitally rendered images ever created way back in the 1970s — Toy Story is the first feature length film made using computer graphics, hence the significance of this reference.
4.Oh, and the name of the realty company that's selling their house is called "Virtual Realty."
5.Andy's handwriting improves as he gets older.
6.In Toy Story, the whack-a-mole–inspired game at Pizza Planet is a reference to the Alien films — specifically, the iconic chestburster scenes.
7.And the carpeting in Sid's house matches the carpeting in the Overlook Hotel from The Shining.
8.Also, in Toy Story 3, this garbage truck's license plate reads "RM237" — another reference to The Shining.
9.Speaking of the garbage truck, did you notice Sid was the garbage man? I'm not sure it's a coincidence that the Shining references have to do with Sid!
10.And in case there weren't enough adult references already, one of Sid's Frankenstein-esque toys is a "hooker."
11."ILL EAGLE" is the name of the company Sid buys his fireworks from... get it?
12.This toolbox found in Sid's house is branded "Binford," a fictional tool company from Home Improvement, which starred Tim Allen (the voice of Buzz Lightyear).
13.Andy's cowboy hat in Toy Story is actually Jessie's hat, who we don't meet until Toy Story 2.
14.When Toy Story 2 opens up, you can spot a Pixar lamp constellation in the sky.
15.Al ends his phone call with the Japanese toy collector by saying "Don't touch my mustache." What he's trying (and failing) to say is "do itashimashite," which translates to "you're welcome."
16.In Toy Story 2, when Hamm is laying out the clues they'll use to track down Woody, he's using the board game "Clue" as a stage.
17.When the toys are cruising around Al's Toy Barn, Slinky complains that they've already been down that aisle. Mr. Potato Head points out that they haven't because the aisle is pink — a joke about dogs being colorblind (a common misconception).
18.And the book Rex is reading in that very same scene is priced at $4.95 in the US and a whopping $50.00 in Canada.
19.Al's Toy Barn sells Bug's Life toys.
20.And Buzz's batteries are made by Buy n Large, the same company that made WALL-E.
21.If you look closely, you can see the heights of Jessie, Rex, Buzz, and others marked on the doorframe in Toy Story 3.
22.Michael Keaton (the voice of Ken) is an alumnus of Kent State University, and Ken owns a Kent State letterman jacket.
23.One of the toys in Bonnie's house is Totoro, the title character of the Hayao Miyazaki film My Neighbor Totoro.
24.In Toy Story 3, you can still see the stitching from where Woody had his arm sewn back on in Toy Story 2.
25.And finally, the final shot of Toy Story 3 is a nod to the opening shot of Toy Story.