Ruined Endings - careful what you read!
This started out as the surprise endings of a few films, until we realised that a good collection of movie spoilers and plot summaries is quite hard to come by. As such, the remit of this site's expanded - just endings are still listed if that's all you want, but there's also the option to list (and submit) a full plot summary for films. Not just the kind of summary you get on the back of DVD boxes, or a review, but a full(ish) account of all the main plot points.
A new site's been started up, devoted to steadily mapping out the entirety of history according to movies. For example, in 1863, while Leonardo DiCaprio was killing Butcher Bill (Gangs of New York), Abraham Lincoln was being kidnapped and taken to the future (Bill & Ted's Excellent Adventure). It's already got quite a few entries, but if you can place a precise event in a movie (to a specific year, if not a precise date/time), send it in and get it on the list!