The Wilhelm Scream is a sound effect recorded for general purpose 'man being eaten by aliigator' type situations and after 1980 had already been used in 30 movies. By then it had become cliche, but more of a movie industriy in-joke. Now, it has been in over 150 movies, including all the Star Wars and Indiana Jones films, Toy Story, Hellboy and a host of others.
A new theatre game is to shout 'Wilhelm' whenever you hear it. A movie compilation is shown here: http://ca.youtube.com/watch?v=cdbYsoEasio
THX-1138 is a science-fiction film made by George Lucas, and became a numerical joke all over the Star Wars franchise. You'd be surprised where you can find it.
The Utah Teapot is an object commonly found in 3D and NURBS programs. Computer Graphics Engineer Martin Newell used it as a refrence object for it's low complexity, saddle points and the fact it had a hole in it. Since, it has been used in many various 3D programs like XSI, Maya and 3Ds Max.
All three of the above can be found on Wikipedia.
Oh, and a "Wedge" character is like a redshirt, except they don't die. A Redshirt is a character that his/her only purpsoe in advancing the story is to indicate danger to the main characters via injury, capture or death. A Wedge character is a redshirt that survives. The name came from Luke Skywalker's friend 'Wedge'. He is in all 3 of the original Star Wars movies, and participated in arial battles like Lukes friends, except they all die, except Wedge.