"Lego Harry Potter is a Lego theme based on the films of the Harry Potter series. Lego models of important scenes, vehicles and characters were made for the first six films and all the books released. The first sets appeared in 2001, to coincide with the release of the first film Harry Potter and the Philosopher's Stone (Harry Potter and the Sorcerer's Stone in the United States). Subsequent sets were released alongside the new films, up until Harry Potter and the Order of the Phoenix. The line then went dormant for three years.
In January 2004, Lego owner and CEO Kjeld Kirk Kristiansen announced a change in direction for the company, which at the time was facing a DKK 1.4bn loss, and that the company would focus on core products and not "big, movie-related IPs such as Harry Potter". A week later, the company clarified that this did not mean any immediate "radical changes", and that the Harry Potter theme would continue. However, the theme was discontinued after 2007 for a time.
In June 2009, it was officially announced by Lego that a video game, Lego Harry Potter: Years 1–4 was in production and released in June 2010. Lego Harry Potter: Years 5–7 is expecting retail release in November 2011.
Warner Bros. and Lego announced on February 12, 2010 that six sets including Hogwarts Castle, Hagrid’s Hut, The Burrow, Hogwarts Express, Dobby's Release, and Quidditch Match would be released in October 2010. These sets have newly decorated minifigures and animals including Luna Lovegood, Bellatrix Lestrange, new owls and new pigs. Also announced was a Lego Harry Potter board game that was made available in August.
Source: Wikipedia, "Lego harry Potter," available under the CC-BY-SA License.