Here's a good way to have many glitches on your crystal game - buy a 2-in-1 game with Pokemon 'Diamond' (i.e. Telefang only bootlegged and poorly translated). It had a number of glitches... let's see. Time was stuck for starters, although sometimes it would jump to a random hour. The day was also stuck, but that I could change by Flying or just looking at the map/etc on the Pokegear (there was even a 'pattern' for it - if I looked at something on the Pokegear in the same way repeatedly the days would cycle in a specific order). That was a rather useful glitch though - I could reset daily events like Viridian House or the Radio Tower lottery.
Speaking of which - I sometimes won that thanks to a mysterious '?????' Pokemon that was apparently in my PC (which I didn't have) which had a matching trainer ID... most odd. And speaking of the PC - box eight was a 'box of doom' - I couldn't take out Pokemon I had put in there because their nickname would change to a million garbled characters that strectch off the screen when one tried to examing the Pokemon and cause it to freeze.
That's on top of a number of other smaller things (freezes or suddenly walking through walls I'm not meant to be able to before the game freezes) - that rarely happened until near Crystal's lifespan. The last thing I remember of the game was encountering a Magikarp...
...which used Explosion on me, freezing the game. I guess that's quite the way to go out with it? XD