The game Chex Quest, which was a total conversion of Doom for kids, used as an advertising campaign and included in cereal boxes. Incredibly well done game.
I mentioned this in another thread on CQ, but can you imagine getting brought into that kickoff meeting and just thinking "great, another soulless marketing game" and then realizing everyone including the client is on board with you making THAT.
Its not like it broke any real new ground (other than a bar for promotional give aways) but in a time when crappy doom clones were a dime a dozen... CQ went HARD.
I watched a video about all these advertisement games and they missed out on the Mr. Pibb shooter that McDonald's was giving out with kids meals in the mid 90's, but the entire second half of the video was all about Chex Quest.
Boffing some of the details here but: poor dude with the last name "Noid" also happened to be some kind of skitzophrenic. So unlike many people struggling with that, people really WERE talking about him... Kinda...
Poor bastard had a multimillion dollar ad campaign with radio, tv, bus stops saying "avoid the noid" which to him was "avoid this man!". If he was receiving help, he would have heard those ads on his way home from his appointments. He would have junk mail through his slot with anti-noid propaganda.
Anyway he took a dominoes hostage. He released all the hostages I think he was the only victim. Just one of those insane things, like anyone else with that surname it would have been a material for their tight five stand up bit a decade later, but in this case it lined up with a man struggling with the exact mental disorder that made it the worst thing possible. Merry Christmas!