There aren't many open source Harry Potter games, but muggle.net has many fun, interactive Harry Potter games available. http://www.mugglenet.com/games/shockwave/index.shtml
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Lego Harry Potter toys can be purchased from the following online retailers: www.amazon.com, www.firestartoys.com, www.toywiz.com, and www.toysrus.com.
google or gamestores such as "game".
Harry Potter costumes can be found on eBay and Amazon and also at various online stores such as Buy Harry Potter Costumes, Wholesale Costume Club, and Costume Craze.
You can find them in many places online.
There are a number of online shops that offer Harry Potter apparel. Some of the sites are Universal Orlando (which offers a wide selection), Zazzle and Alivans.
You can find Harry Potter PC game here http://download-free-movies-games.blogspot.com/2009/06/harry-potter-and-half-blood-prince-PC.HTML And you can find lots of games in http://download-free-movies-games.blogspot.com/search/label/Games
go to any bookstore, or any online shopping site, and 100% chance you will find harry potter books for sale.
In a book store in Spain maybe or online.
ii found it in harry potter
Check online.There are alot of online t-shirt shops that carry vintage t's and such.
Wal-Mart sells a lot of Harry Potter products, including the books and movies, video games and musical scores. They do not sell any Harry Potter toys online, however, you may find some in your local store, especially when there is a major release like a new DVD.