Don Adams was an American actor, best known for his role as the incredibly skilled yet incredibly clumsy secret agent Maxwell Smart in the secret agent spoof sitcom Get Smart. If you don't recognize the title—which, fair enough, it aired literally sixty years ago—he also notably voiced the dimwitted cyborg police officer protagonist of the Inspector Gadget cartoons.
He has a Ryu Number of at most 4.
The last portion of Space Quest V: Roger Wilco – The Next Mutation features our titular protagonist infiltrating the SCS Goliath, making use of its cramped, labyrinthine maintenance tunnels.
Apparently someone in development thought the passageways a bit reminiscent, video-game-wise: Take the right wrong path, and Roger will speedily crawl in the other direction with an unexpected cameo on his tail.
Space Quest 6: Roger Wilco in the Spinal Frontier is fully voiced, including—as you may know already because @ryunumber—noted disc jockey, announcer, and voice actor Gary Owens. Normally this wouldn't be enough to count the actor themselves, even if they are credited in the game—but persist past the end credits and fade-out and you'll hear the narrator thank you for playing Space Quest 6 before extroducing himself specifically as "Gary Owens, signing off." Totally counts!
Finally, guess who got himself a copy of TV Land Presents Blast From the Past?
Mind, it's such a jalopy of a game I couldn't get it to run on my computer without serious graphical issues...
... but I was able to get it to run just runnily enough to confirm its nature! If you ever wanted to play a game where TV stars of a bygone era ask you trivia questions about the shows they were on... then you're not exactly choked with options, are you?
Gary Owens pulls double-duty here, playing both quiz host and TV star questionmonger, his questions focusing on the sketch comedy show Rowan & Martin's Laugh-In (where he was the on-screen announcer).
Don Adams' questions, of course, have to do with Get Smart. Unfortunately, I couldn't get any clean, non-glitched-out footage of him from my recordings, so have this video I extracted from the game files instead.