A free download-only Windows game designed and released in 2003 by Alasdair Forsythe. Inspired by the wildly successful Tony Hawk's Pro Skater franchise, it won the 1st prize in the GML Design Contest 2003. The game is with the minor internet meme "Stephen Hawking's Pro Wheelchair" that appeared years later, and which was about an imaginary game.
Pro Wheelchairing didn't impress with a lot of content, sporting one map and one playable character - Stephen Hawking, an aging man in a wheelchair who just happens to have the same name as a world famous scientist. The graphics were simple even for a free DIY effort, yet the gameplay struck me as highly enjoyable. While the number of tricks in Hawking's portfolio was limited, the skatepark included halfpipes, slopes, rails... and teleporters. With a little practice it was possible to grind for minutes on end in order to amass points. In contrast to typical sports games, death was an option.
Mysteriously, it seems that, a few years after its release, the game disappeared from the internet. None of the download links work anymore and most references have been deleted. Pro Wheelchairing is not available, or even listed on the developer's site anymore. When yielding a web search, the vast majority of results concern the above-mentioned meme. Basically all the proof left of the game's existence is the GML contest's site, which at least includes a screenshot.