Don't know if anyone can help me. Remember that silly tune sang by that silly techno-billy band, The Cartoons? Everybody sing a song, doo-daa, doo-daa, everybody sing a song, all doo-daa-day... (something like this) But I heard it also in a Mel Brooks movie, and a friend told me it was sung also by some Warner Bros cartoon character. So may be it a folk song?