I Love Glitches...

[Axel Akutare]

In Rumble Roses XX, when you play as Miss Spencer and just hold left and keep using the grapple button, you get an inescapable infinite combo that does nothing but body damage and fills your enemy's H-meter, allowing you to do an inescapable H-move.

Also, in Naruto: Gekitou Ninja Taisen 4 on the Gamecube, you can freeze the game by using Curse Seal 2 Sasuke's Giant Fireball and Kyuubi Naruto's Power Attack at the same time.

Finally, in Digimon World, when you recruit Giromon into the city, he unlocks the Sound Test. If you try to use it at all, the game Freezes.

[Lucia]

Once, I managed to glitch through a wall in La-Mulana, making one of the most frustrating non-vertical areas a bit easier. Given what an absolutely evil game La-Mulana is, that deserves points.