From IndyHall Labs:
Movies are meant to be loved - that's why you have so many. But managing your movies' metadata can be a pain. There are other programs can help, but none quite as simple and beautiful as Multiplex. Combining the true power of Mac OSX with an emphasis on simplicity and just a touch of eye-candy, Multiplex lets you catalog your movies,retrieve metadata for them through the internet, and play them. It knows what movies are available at any time. Attach an external hard drive, and Multiplex immediately shows which movies are now available to you. Incredibly simple searching can find the movie you're looking for in just a few keystrokes across hundreds of titles. If you have movies on your hard drive, Multiplex will automatically find them the minute you launch Multiplex for the first time. Pop a DVD into your drive, and Multiplex will automatically recognize it. You can search for metadata using a movie's title or UPC code - and editing that data couldn't be easier. Multiplex even plugs in to the DiscIdent.com service to recognize your discs and download metadata automatically when available. It's never been this easy - or fun - to manage your movies.