When I say "Ripley's Believe It Or Not," the first thing that will probably come to most people's minds is a TV show, a museum, or even a book series. Most people will probably not think of Robert L. Ripley himself, and I'm not sure how many people know that Ripley got his start as a newspaper cartoonist.
His first full time gig was with the New York Globe as a sports cartoonist. At the time, the comic panel he drew was called Champs and Chumps, and would normally feature various sports facts and stories of amazing and unbelievable athletic feats. As time went on, Ripley would often include other interesting facts not related to sports. In the end, he dumped the sports theme entirely and renamed the panel "Believe It Or Not!"
I say he got his start as a cartoonist, because that's certainly not all that he did. Most of the other things that we associate with the "Ripley's Believe It Or Not" brand are things that Ripley himself started. His cartoons and facts were collected into several books, he opened museums and exhibitions featuring odd, unbelievable things (which he called "Odditoriums"), and he was able to appear on the first season of the Believe It Or Not TV show. Unfortunately, he died before the first season finished, but the show continued on, and all of those other things continue to this day. There are many Believe It Or Not museums around the world, there have been three different TV series, and many books are still published under the Ripley's banner. The comic panel itself also survives, now written and drawn by John Graziano.
The other interesting thing about the comic panel is that it spawned a large number of imitators, so many in fact that it became a genre unto itself. Most of the imitators concerned themselves with oddities of the local area where the newspaper was published, and they can be very interesting pieces of history if you happen to find them in old newspaper archives.
Some links for further info:
Believe It Or Not at Don Markstein's Toonopedia
Robert L. Ripley at the Lambiek Comiclopedia
The current Ripley's Believe It Or Not comic panel at Universal Uclick",