***SPOILER WARNING FOR MI2: LECHUCKS REVENGE***
There's a lot of banter about the 'real' meaning of the games ... the most popular and obvious being that Guybrush and LeChuck are childhood brothers lost at Disneyland in real-life and are 'make-believing' the entire game into existance.
This is seen at the end of Monkey Island 2. The original writer, who only did 1 & 2, has said there were only meant to be the two games - Monkey Island 2 is really the end - but LucasArts 'tacked on' another two games to milk the cash cow.
There are websites around that support this theory by picking the games apart piece by piece and relating real-life references & in-game locations to real-life locations at Disneyland.
When you think about it, there were taped off areas, 'staff only' doors and soda machines, to name a few. It would be interesting to go back through the two games knowing all this and try to pick them all out
On a different note I thought it was hilarious that in MI3, after Guybrush marries Elaine, that everyone refers to him as Mr Marley