Sega made a ton of obscure and rare Sonic The Hedgehog games. One of those games happens to be an arcade title called Waku Waku Sonic Patrol Car. It's a game about Sonic being a patrolman and attempting to stop Dr. Eggman.
Sonic Retro discovered that this off center arcade title is now compatible with MAME, the multi-arcade machine emulator. That sounds simple enough but it was actually a process to make that possible since finding a working PCB board to dump the ROM from was a task in itself and then they had to ship the unit from the store location to the ROM dumpers home.
In the comment section of the article someone who claims to have been involved with getting the funding to ship the unit states that gathering donations to turn Waku Waku Sonic Patrol Car into a ROM was difficult because the IndieGoGo didn't generate enough funds to cover all the costs and that shipping the entire unit ran north of $3,000. That's not too surprising.
According to the website there weren't many working units that could be found in the wild. One of the units they did find had a broken steering wheel. Eventually a working unit with a working board was found. You can see how the game plays out in the video below to get an idea of what the Sonic game is like.
Essentially Sonic is a police patrolman and players using the steering wheel to dodge obstacles on the road. The music and sound effects are based on the original Sonic The Hedgehog. The game allows you to weave between traffic, hunt down Eggman, battle him in Sonic's patrol car and go home a hero.
As mentioned in the video, the game is designed for little kids so it's not really possible to lose. The game doesn't appear to have been translated outside of Japan and Sonic still speaks in Japanese in the arcade title. According to the copyright screen the game was made back in 1991, so this was shortly after the launch of the original Sonic game.
It's pretty cool that some preservationist have managed to get their hands on the board and dump the ROM for MAME. If it weren't for them a lot of these games would literally be lost to time. Most companies aren't keen on letting their IP go into the public domain and there have been a lot of back and forth squabbles over games being legally accessible through ROMs for use in emulation or through peer-to-peer sharing. The EFF also tried lobbying Congress to make it where gamers, modders and hackers alike could use third-party means to revive defunct MMOs, but they ran into some serious opposition from the ESA.
ROMs and emulation are not looked upon fondly in the world of corporate gaming, but through said emulation it enables gamers to experience rare titles like that Waku Waku Sonic Patrol Car.