Casting brought in producer/performer Anthony Begonia to improv audition an unscripted Hawaiian bartender line which didn't make it in the film right before the "Flaming Tornado" is unleashed.
The dragon head katana on Mr. Thompson's desk is the same type made popular by the character Duncan McLeod from the TV show "Highlander" (1992).
In one scene, Dupree is running through a parking lot looking for Carl. In said parking lot, you can see the yellow van from the movie Little Miss Sunshine (2006), which was in production around the same time.
The interior shots of Molly and Carl's house are filmed on the set of what used to be Hope and Michael Steadman's house on the television series _thirtysomething (1987)_
Carl and Molly's house, although it is blue, is the same house used at the end of _13 Going On 30 (2004)_ , where it is pink.
The bumper sticker on Mandy the librarian's car reads "Do the Dewey". Dewey is the decimal system for cataloging library books.