Previously reported Glitches for KOTOR 2.
If you're on Korriban and run into Juhani's old boyfriend or whatever, he will show up at the cantina in the dreshade. You do have the option to kill him, but what was weird was that if you kill him, get out of the dreshade and go back to the cantina, he will be standing there like nothing happened. This is a great way to get jedi knight robes and the Eralam Crystal and some exp, but you wont get dark side points.
Sith Armour Glitch
There's also the Sith Armour glitch on Taris. This allows you to keep the Sith armour even after you give it to Gadon for the identification papers. If you give Carth the armour and talk to Gadon, Carth still has the armour and you have the papers.
Super Saber Glitch
The Super Saber Glitch requires multiple lightsaber crystals of the same type.
1. Take the lightsaber you want to make into a super saber and remove all of the crystals and choose your colour. Note that once you have made the super saber, changing the colour will remove the glitch and reset the saber.
2. Place a crystal in the top power crystal slot. Press the assemble button and leave the work bench. Save. The crystal should be in the bottom slot when you re-open the work bench. Place another crystal of the same kind in the top slot.
3. Assemble the lightsaber and save. When you re-enter the workbench the crystals should have stacked. Repeat until saber has desired damage.