The term for the
event and the
enlightement that occurs when either:
You hear a sample in a song and recognize the origin of said sample
or
You listen to an audio recording (or the audio track of a motion picture) and can recall a song that utilizes a sample from said recording.
This occurence used to belong to those who listened to rap/hip-hop and techno music. Since their influence has seeped into the mainstream, even listeners of pop music have had the fortune to experience this.
Examples:
Listening to Robbie Williams' Millenium and suddenly exclaiming, "Hey, that's James Bond!" Of course, if you were watching the video, you were pretty much smacked with a gargantuan ClueStick.
Listening to Orbital's Moebius and your eyes light up as you say, "Isn't that Worf from Star Trek?"
Listening to a techno song and momentarily stop dancing to absorb the fact that the song just sampled Blade Runner.