You won't find a fanbase more rabid than the one for Harry Potter.

The stories of a young boy who finds out he's a wizard, grows up at a mgical castle and fights Voldemort, this series has spawned more overpriced crap than anything short of Lord of The Rings.

There are seven books, (all of them released as of July 21st, 2007) and five movies currently. The movies suck. Read the series.