Before Lance jumps into the pool to save Shaun, he takes off his socks. This was not in the script but was an idea of Jack Black's wardrobe assistant. Black found the idea hilarious and the gag remained in the film.
The web address written on Shaun's keyboard (seen while he is writing at the beginning of the movie) is 'www.thrashermagazine.com', the site of "Thrasher", a monthly publication mainly devoted to skating and surfing.
Mike White & Jack Black have starred in multiple films together other than Orange County. Richard Linklater's "School Of Rock", Jared Hess's "Nacho Libre" & the 2015 dark comedy, "The D Train" directed by Jarrad Paul & Andrew Mogel.