This sound is from The Joker (Heath Ledger) Soundboard

Ledger's Joker also explores techniques found in the actor's previous performances, including his clown act in Terry Gilliam's fantasy film The Brothers Grimm. The film was released in July 2008, six months after Ledger died of an accidental overdose. The Joker embodies themes of chaos, anarchy and obsession throughout the film.
See also: Heath Ledger, List of accolades received by The Dark Knight, Joker (character), Joker in other media, List of awards and nominations received by Heath Ledger, and Rachel Dawes.