It's a typical Rails 3 apps, Nokogiri used for scraping, PostgreSQL db (migrated from SQLite originally), jQuery+ui for the aucomplete (lazy, yay!), and that's about it :)
Re: foreign languages, they store very tidy information about all the available titles (basically a mapping from ISO 3166-1 to the title), cf. http://help.themoviedb.org/kb/api/movie-alternative-titles
Thanks for the feedback!