Disgaea 2: Cursed Memories/Cave of Ordeals
Here's a great powerleveling strategy for the first stage in the Cave of Ordeals. Here's what you'll need: two beast tamers, two warriors, male or female, the character you want leveled, and about six thieves.
First, get triple experience and the strongest enemies. When you have it, go into the Cave of Ordeals first stage, take the first warrior, and put him as many spaces as he can walk away from the panel, towards the geo symbol north. Take the second warrior and have him stand just one space north from the base panel, and have the character you want leveled up stand on the base panel. Now lift the character you want leveled, with warrior two and throw him to warrior one. Have warrior one throw the character just one space south of the geo cube thing. Move the character to the left of the cube, lift it, and throw it onto the red space, but don't end the turn.
Now move a thief to where she's standing next to the two top left archers. Lift the one to her left, and throw it on the one to the north. Now move the beast master to the right of the archer, lift, and throw her onto the other archer to the far right. Move another thief over there and lift the archer north to throw on the archer to the right, then end the turn. The thief who threw the archer is going to die, but that's okay.
Now move the character south, and move the upper left rogue to that geo cube and throw it somewhere that the archers won't get its effect. The beast master should be right by warrior one. Lift warrior one and throw him to the red panel near the archer that just killed your thief. The archer should be about level 1,343 by now, so move warrior one south of her, lift the archer, and throw her onto that archer south. Using the rogues, complete this cycle until only one archer is left – you can do it all this turn. Now move another rogue to the left of that archer, and use the steal consciousness move, so she's asleep. Move all the geo cubes except the experience +50% off the tiles, and move far south and put that geo cube on for another +50% exp. Now you have +100% exp and an archer standing on it at level 2,786 and she's asleep and harmless, plus the triple exp (if you grabbed it) that's six times exp for a level 2,786.
Move your the character so they are behind the archer. Now, using the rogues, use steal health and steal consciousness, then wait three turns. Use heal on the archer, then steal health and steal consciousness again. Wait two turns and use espoir so she's not poisoned, and use steal consciousness again. She should only have a little health left, like 400. Usually exactly as much as you healed her for. Now just hit her. If she doesn't die, use steal consciousness and end the turn. Just keep repeating that, and then you get the exp for six level 2786 archers, and because of the sleep she's harmless. Usually you'll make level 110+ from level 1 in just that single round. You also make 29 million hell and about 4,000 mana a round.