I found a funny glitch on Spyro: Year of the Dragon for PsX.
To activate it, do the following:

Go to any world with lava or any other kind of stuff that makes you hurt yourself. I prefer to do this in Molten Crater in the Sunrise Spring homeworld at the beginning of the level, but it can be done anywhere. Jump into the lava, keep burning yourself untill Sparx is gone. What you want to do now is hit the ava one more time, but as you hit the lava, quickly pause the game. You'll feel the controller shake if you did this correctly. Now, don't unpause the game, select 'Exit world'. You'll return to your homeworld again.

You're technically dead, so you can do pretty much anything you want. You can't pause the game, or even peek into your Atlas though... You can even step through other portals after the glitch is activated, you can even go to other homeworlds. One little hit though, and you're dead. Oh, and swimming is a no-no. Cuz when you jump into water, you don't start swimming, you'll keep falling until you reached the bottom of the lake. This can be fun at first, but after a few minutes of wandering around aimlessly, you'll get bored. What to do? Well, pause the game of course! Oh, wait you can't... The only way to get out of there is turn off your game system. Seriously.

My advice: GO TO SEASHELL SHORE. I do it all the time. The fun thing is, you already start the level in water, so you don't automatically fall to the bottom. In this level, you keep swimming. When you start in Seashell Shore, swim over to that little shell castle thingy at the other side of you. Avoid getting hit at all cost, you don't want to get hit. You will reach surface eventually. When you reach surface... Well, go try it out once, I'll keep it as a surprise for you(trust me, you'll like it!). To end this glitch, step through a dark protal, or simply, let Spyro die.