Monkey Island 3a: The Secret Revealed or your Money Back
From Monkey Island wiki
Monkey Island 3a: The Secret Revealed or your Money Back is a hypothetic adventure game Ron Gilbert said he would like to make. It would be an alternative version of Monkey Island 3, revealing the real Secret of Monkey Island. According to Ron, he even contacted LucasArts about it and they were interested, but then "it just ended". Back in 2004, Ron wrote on Grumpy Gamer that "if he wins the lottery, he'll buy the right to Monkey Island" and create his game. The phrase about lottery became a well-known joke among Monkey Island fans.
A 2010 article in Retro Gamer states that Ron is still interested in the idea, but since "he's not the same person he was 20 years ago", "it would be a different game than he had planned".
After LucasArts and all the properties established within the company were bought by Disney, Ron Gilbert voiced his continued hope to make another Monkey Island again. In an interview, Gilbert voiced his intent to contact Disney and hoped to negotiate a way to either make such a game through a partnership or acquire the rights to the series once again to make it himself with no restrictions. Ron was also quoted as saying that while he is still extremely invested in continuing the franchise, he is not too optimistic that Disney would allow him the rights to the series or make the game as he does not possess the financial means to acquire them through a buyout and the fact that Disney has many other properties that would attract a more mainstream audience within the video game community. As of now, the future of the series seems to be dependent on Disney's decision should Gilbert make any direct contact with the company and form negotiations.