When they first started filming, Amanda Bynes couldn't play soccer at all. Nevertheless, Bynes does most of her own playing in the movie.
As Duke comes into the shower room and walks by Malcolm, he snaps the towel at Malcolm's head to get him to shut up about the dorm pamphlet life while ranting at Sebastian. Channing Tatum really hit James Snyder in the eye with the towel and James' reaction is real.
In the double date scene, as Eunice is sitting down, Amanda Bynes ad-libs the phrase "Lady pterodactyl." In fact, most outbursts were improvised, like David Cross inviting Sebastian to "have a nice apple and sandwich."
In 'Twelfth Night' (on which the play is based), Olivia has a steward named Malvolio who is in love with her. The character of Malcolm is based on him and has a pet tarantula named Malvolio.
When holding auditions for the role of Duke, Amanda Bynes fought for the producers to choose Channing Tatum, who at the time had never had a leading film role and was largely unknown in Hollywood. Producers also were concerned that he was significantly older than most of his costars. Tatum credits Bynes with helping him launch his career as an actor.