Boingboing ganked the scan without credit--plus he called it an AT-AT, when it's clearly an AT-ST/Chicken Walker, duh--but the ad for the incredible Gym Dandy Scout Walker Command Center With Speeder Bike Ride backyard playset was originally from the October 1984 issue of Woman's Day magazine. It was found by Shawn, the genius behind the childhood flashback blog, Branded in The 80s.
Anyway, I'm not posting the ad here, because you can see it just fine where it emerged.
I will point out, though, that I can't find any recall notices for the Command Center, so quitcher bellyachin' about how dangerous it looks; and isn't that exactly part of its appeal, you old man?
And also, hey-o! Holy crap! The Speeder Bike Pedal Car! According to the official Star Wars Cargo Bay collector's database, these were made by Huffy for Kenner as part of a sweepstakes. And according to Bob Fields, whose example here is included in the Star Wars Collectors Archive, there were 200-300 of them out there at one point. May the eBay Force be with you.
UPDATE FIVE MINUTES LATER: Nothing's rare on the Internet! Here's a photo of the Speeder Bike display from a KMart. And there are at least three less-than-mint pedal Speeder Bikes on eBay right now, for what seem like high prices!
The worse the condition, the higher the price, go figure.