Box Office Mojo
Box office site featuring Hollywood Stock Exchange columnist Brandon Gray and his Box Office Forecast, the most accurate predictions on the web. Also features all the latest box office data, and release schedule.
The Movie Predictor Home Page
This site looks promising to allow you to try and predict box office numbers, especially the estimated delist price on HSX. Simple, direct, but oriented strongly to HSX fans.
The Numbers
Bruce Nash's excellent compendium of box office numbers organized for current movies currently in release as well as historical data for box office figures. His list of the top 100 films of all time is also quite interesting.