It's probably not happening anymore, though. Jim Carrey has left the sequel, titled Dumb & Dumber To (presumably that's a joke playing on Lloyd and Harry's inability to distinguish "two" from "to"). Anonymous sources reported to Entertainment Tonight that the actor was frustrated by what he felt was a lack of enthusiasm on behalf of Warner Bros. and New Line. Carrey confirmed as much, issuing a statement saying, "I would have thought Dumb and Dumber To was a no-brainer, after all it's implied in the title."
It's unknown exactly what form this perceived lack of enthusiasm took. Perhaps Carrey's compensation was not up to snuff. It's possible that the WB and New Line were waffling on the September start date or the project's budget, particularly after the Farrelly Brothers' last few movies, The Three Stooges, Hall Pass, and The Heartbreak Kid, haven't been runaway successes.
Whatever the case, Carrey has cleared out of what would have been his first sequel not borne of contractual obligations, as was the case with Ace Ventura: When Nature Calls. It doesn't seem likely that a sequel will proceed without him, especially if Warner Bros. already wasn't super-stoked about a follow-up. When the Farrellys, Carrey, and Daniels weren't chomping at the bit for another Dumb & Dumber, New Line went ahead with a prequel. 2003's Dumb and Dumberer: When Harry Met Lloyd, which featured Eric Christian Olsen and Derek Richardson as Lloyd and Harry, predictably failed to connect with audiences.
Considering that the first film earned $247 million globally on a budget of $16 million, it made sense that New Line, Warner Bros., the Farrellys, and Daniels would hop aboard after Carrey suddenly felt the urge to return to the characters.
Last October, Warner Bros. hired Sean Anders and John Morris, the writing duo behind Sex Drive and Hot Tub Time Machine, to write the Dumb & Dumber To script. That's My Boy director Anders recently talked exclusively to IAR Managing Editor Jami Philbrick about the sequel screenplay, and you can check out that interview by clicking here.
Unless things turn around and Carrey comes back, however, it looks like their efforts will be for naught. Harry Dunne and Lloyd Christmas will forever remain as we last saw them, walking along a desolate stretch of road after moronically missing an opportunity to oil up a busload of Hawaiian Tropic bikini models for a living.