Miffy (Nijntje in Dutch) is a world-famous rabbit cartoon character. She was created by Dick Bruna (the museum used to be called Dick Bruna House).
At the moment (August 2015) the museum is closed for a total makeover, until December 2015.
According to the website, 'the Dick Bruna huis will be transformed into the most delightful children's museum in the Netherlands: the Miffy Museum.'
Nijntje (in English: Miffy)