I remember a contest that ran just the first second or two of a song – sometimes just the first note (!) and the caller had to identify the song. The contest song nuggets were pre-produced onto tape, and the announcer could play the same “nugget” more than once if the caller was having trouble identifying the song. There were always the easy ones to identify, guaranteeing a winner.
But then there were the difficult ones – sometimes a very popular “oldie” that sometimes took several callers to get it right. The harder contests might span an hour or more by taking one caller at a time until someone finally got it right. The reward would be a prize, -AND- you got to hear the entire song from beginning to end.