A playable demo is now available for LEGO Harry Potter: Years 1-4 Demo, the upcoming action/adventure from Traveller's Tales that combines the magic of LEGO with the simple construction of the Harry Potter series (or something like that). The demo is available on this page, and it is mirrored on AtomicGamer and FilePlanet. There is also a new launch trailer for the game, which is expected for release next week. The embedded version of the trailer follows.