Karaoke Flashback
When you were so drunk on the weekend that you can not remember singing a certain song on the karaoke machine, and a few days later when you here that song on the radio it all comes back to you.
Gee, Ive just had Karaoke Flashback!, i must of been drunk on Friday night because I had no memory of karaoke singing 'Paradise City', I would of never remembered if I had not heard it on the radio today.