(Sourced from Wikipedia:) The phrase Law of Attraction, used widely by New Thought writers, refers to the idea that thoughts influence chance. The Law of Attraction argues that thoughts (both conscious and unconscious) can affect things outside the head, not just through motivation, but by other means. Essentially, "if you really want something and truly believe it's possible, you'll get it", but putting a lot of attention and thought onto something you don't want means you'll probably get that too.
Widespread popular interest in the Law of Attraction reached its peak after the release of the The Secret, a 2006 film by Australian television writer and producer Rhonda Byrne. Byrne followed up the film with a bestselling book of the same title and appeared on a series of talk shows in 2007.