I recently started reading https://www.reddit.com/r/softwaregore/ (the one link I get a day in my email), and it's always interesting.
My favorite video game glitch might be this Super Mario World code injection https://www.youtube.com/watch?v=voL3e0iqugo&t=63s&ab_channel=SethBling ... I was actually looking for the one where they jump to the end credit scene, but this one might be even cooler because he gives himself a nonexistent powerup.
For computer glitches, I had one in mind but I can't find the article. Basically Microsoft had a sophisticated secret way for the Microsoft webpages to elevate privileges in their browser to run arbitrary code or update the OS or something, idr, and someone found a simple way around it that apparently the programmers at Microsoft hadn't thought of, so it was kinda funny.

I spent a whole day at work last week doing meetings and discussing various options we had to try to avoid an annoying "feature" of Outlook. Paying customers of Office 365 can get a thing called "advanced threat protection" where every link in email is changed, so when you click you get to a Microsoft server that first opens your link in a sandbox before redirecting you. That breaks confirmation emails or "magic link" authentications because this "virtual click" causes links to expire, and it was interesting to look at all the ways other people in open source projects have tried to fix this. Ghost adds a 10 second timeout after the first access to the link where you can still click to login, some other projects detect the IP of that specific server to redirect it somewhere else, etc.

when I was little, we had a game genie cartridge for the NES and would type in random codes to see what would happen. I was like...6 or 7 at the time? and my 2 years younger brother was like "let's put in a dirty word" so he put in the filthiest swear we could conceive of as children: butt fart poop stink.

if you put this awful swear into the game genie for super mario bros. for NES, it glitches out the characters and the music becomes very strange and I was so scared that I thought we had "upset" the game genie (being a smol child I didn't fully realize that it was a computer program and thought perhaps a genie lived inside of the cartridge lol)