Some of the guests who came to the premiere of the film include Wendie Malick, Joey Lawrence (Andrew Lawrence's (T.J.) older brother, who was also the voice of "The Dude" in the show), Dylan and Cole Sprouse, Michelle Trachtenberg, and Myles Jeffrey (Who would become T.J.'s new voice actor a few years later), among others.
Non-Singing Voice: Mikey, as usual, but when the kids are singing backup in "Green Tamborine", a few of them have different voices. Blake Ewing, who usually voices Menlo (who doesn't appear in the movie), did T.J. and Gus's singing voices (Blake Ewing's little brother, Zach, would eventually voice Gus in the Lilo & Stitch crossover), while Anndi McAfee, who voices Ashley A., did Gretchen's singing voice. Pamela Segal and Rickey D'Shon Collins did their characters, Spinelli and Vince, as usual.
Though oddly enough, any other scene with the kids singing has them sing with their regular voices.
What Could Have Been: It was going to be released for summer 2000, just in time for summer vacation, the theme for the movie. Because Pokémon The Movie 2000 was being released at the same time, Disney feared competition from the mentioned Cash Cow Franchise and kept on pushing the movie back until February 2001...which was far from summer vacation (unless you live in the Southern hemisphere, though at least it was released during the usual week for February vacation!).
Though if both were released at the same time, Pokémon would've done better in terms of raking in the dough at the box office, while Recess would've been more favored by critics (Which was pretty much the same in critical terms for both shows on TV as well)
Summer Vacation: The Ultimate Recess was the original title for the movie before it was changed to the much-better sounding title it has now.
After the gang leaves T.J. for camp, there was going to be an original song by They Might Be Giants playing as he sadly rode his bike alone. It was replaced with "One".
In the ending credits, Mikey was going to sing "Get Back", but it was too expensive to get the rights to a song by The Beatles. They used "Green Tamborine" instead.
The film was also going to be released direct-to-video, but because of the show's popularity (And Disney's enthusiasm for the film), it got an enormous production overhaul for theaters, and proved to be a success.
The DVD was advertised as going to include some deleted scenes as bonus features, but they were never included.