User blog comment:E-114/The Gift Cards/@comment-1903616-20100321154914

I know a cool glitch that let's you complete Pokémon Green in 5 minutes. Weird, huh? I can't explain it, though. I can explain the Old man glitch though: Tada! You did it. ;)
 * 1) Talk to the old man in Viridian. Let him catch the Weedle.
 * 2) Without stopping, fly to Cinnabar.
 * 3) Don't stop! Go straight to the edge of Cinnabar (up and down one).
 * 4) Use Surf and go up and down. You encounter MissingNo. It will usually have a level that is higher than 100.