I heard one actually while riding the ferry in Sydney Harbor; it was quite funny, and I recall parts of the tune (useless unless I can hum it to you) and practically none of the lyric, but there was something recurring involving "on a Sunday afternoon" and also a bit about, I believe, "let's go to the beach and take off our clothes, and then we'll see who's Manly." The pun sticks in my mind of course. It was a lively recording with a band of probably four or so players and a young-sounding male singer with backup on the chorus. (That doesn't narrow it down much, does it?)