The first time I heard it was in England in the mid-1980s when the sign in the Camping Gear Shop was supposed to have read:

"Here is the Winner of our discount tent"

Sounds more like the late Ned Sherrin circa 1967 to me.

Ned Sherrin .... Mmmmmmmh!

I was a lad in short pants when I first heard that, and now, alas, I am a man of grey beard...

I guess it demonstrates a life spent assidusously avoiding anything like camping. A result of a country childhood, I expect: the great outdoors holds no romance, when it means a hard cold lumpy bed and no coffee in the morning, and I'd rather a hotel than a tent any day. Still, it amused me hugely this morning. Doesn't take much...

I googled "The Winter of our Discount Tent" and it is indeed a very old and widely travelled joke. However your post is the first time I've come across it and it amused me hugely too.

It made me recall a sign I came across on a building in Boston advertising a fictional law firm called "Dewey, Cheetham and Howe". (Though I only found out it was a joke much later.)

I claim authorship of "now is the winter of our disco in the tent" (about 30 years ago)... About 219,000 hits for disco-tent tho!

I'd never heard of it before (and I own two tents), so I'm glad you posted it. Made me snortle.