Along these lines, I also seem to recall that in about 1971 or 1972, the Royal Scots Dragoon Guards (a bagpipe band) had some success on the charts with “Amazing Grace.” Note that I’m unsure just how much success they had, but I do recall that they got a lot of airplay on my local Top 40 station.
Didn’t the actual theme from Star Wars enter the top 40 in the 1970s? I’d also add the theme from Chariots of Fire.
Spoons- #11 on the US Top 40- not sure in Canada.
In The Navy you can sail the seven seas
In The Navy you can put your mind at ease…
And War’s Why Can’t We Be Friends
Song apparently no one remembers but me:
Chirpy Chirpy Cheep Cheep 
Rick Dees’ “Disco Duck”
One Night in Bangkok made #1
And who could forget “Gimme Dat Ding” by the Pipkins.
Shoot…I bought the album!
There was that period in the early '60s of morbid death songs: Teen Angel, Last Kiss, Tell Laura I Love Her, Leader of the Pack. And we think kids then were so wholesome…
Werewolves of London. Unusual subject matter.
What’s even stranger is that Meco’s disco version did better on the charts than John Williams’s original.
My personal favorite Top 40 oddity: Jim Henson’s Rubber Duckie, #16 in 1970. Yes, the song from Sesame Street.
I have that 45 somewhere.
Mnah Mnah, also by the Muppets.
Well, I certainly TRIED to… 
And thanks to you, I now also remember Troglodyte by (IIRC) The Jimmy Castor Bunch.
And Basketball Jones by Cheech y Chong.
How could anyone nominate White Rabbit? The 60’s were ALL ABOUT drugs!!!
DOA by Bloodrock is the only song describing dying in a plane collision, ever to get airplay. It may be the only song on that subject, period.
It was playing on the first station I came to rest on, the first time I moved the dial off my parents’ middle-of-the-road station to see what else was on the radio. It was so weird I had to listen to that station until I heard that song again.
“Pass the Dutchie from the Left Hand Side”
“Mambo Number 5”
the dead animal sub-genre:
“Shannon” and
“Wildfire”
and the frequently mentioned:
“I’ve Never Been to Me”
Didn’t “Everybody is Free to Wear Sunscreen” make the Top 40 in the late 90s? Right about when I was graduating, in 1999.
Baz Luhrmann, new-agey music, a choir, and lyrics that consist entirely of spoken-word glurge attributed to everyone from Kurt Vonnegut to my high school guidance counselor to Dear Abby.
Is that the most recent nomination? Or has anything so weird happened since?
Spill the Wine by Eric Burdon ( that overfed long haired leaping nome…) & War
and My Boy Lollipop by Millie Small
IIRC, the writers of “Timothy” later claimed it was about a burro.
I nominate “The Thing” , by Phil Harris: #1 for several weeks, and a great drinking song to boot (the line “and then I took it home with me to give it to my wife” has sounded funnier than it did the next morning for generations).
In the mid 1960s, then U.S. Senator Everett Dirkson hit the charts with a spoken word version of a song called ‘Gallent Men”. The song was co-written by television news reporter Charles Osgood. The record received a grammy award.
Near that same time, Mrs. Miller , a middle-aged woman who seemed to sing slightly off-key and off-tempo, gained fame and hit the charts with a cover of Petula Clarks’s “Downtown”. She also released a couple of albums, which sold fairly well for a couple of years. Image a slightly warbly sounding sort of high pitched voice, and you’ve got it. Some people said she sounded like Tiny Tim’s mother.
I remember that one. From 1973.