What blockbusters have we forgotten about?

I've actually never seen Cutthroat Island, though I know it's one of the biggest bombs of all time. (Actually, reminds me of the kinda movie I'd like, though.)

As for Superman Returns, maybe, but I don't remember its being that big of a splash even when it was released, though. I still find it perhaps the most underrated superhero movie of all time.

The Amazing Spider-Man, definitely. There was so much put into it, and it was just something of a dud, forgettable and therefore soon forgotten. 

Actually, there are surprisingly many blockbusters that just seem to have been forgotten. The remakes of Get Smart and Underdog, which I saw at a drive-in one summer (and mentioned on another thread), have been nearly completely forgotten. In fact, I only remember them because I did see them at that drive-in.