The year was 1965, probably May. Based on Mr. Jordan's commentary, I would guess that "Mrs. Brown You've Got a Lovely Daughter" was #1 that week. It was #1 on Billboard's Hot 100 for three weeks, beginning May 1, 1965.
I had forgotten that Chubby Checker ever did a song about "The Freddie". It peaked at #40 on Billboard's Hot 100. Freddie and the Dreamers had the version ("Do the Freddie") that I remember, even though it peaked at only #18 on Billboard.
But the real trivial pursuits question that goes with the Freddie and the Dreamers version is: "Name one of the two legitimate Top 40 hits heard on Lan Roberts' Garbage Record Festival (Oct. 31, 1969) on KOL Seattle." The other, by the way, was "I Love Onions" by Susan Christie from 1966.
If you want to see if my memory is correct, you can hear it for yourself at
http://www.reelradio.com/jp/index.html#lrkol69-1I see that Radiofan posted his answer between the time I started typing this and the time I finished. Let's see how close I was.