Dragon 275
Crescent Knife: 20 gp 1d3 crit: x2 slashing

Each attack is actually two separate attacks.
Add Aptitude.
Learn lightning mace and roundabout kick.

You attack twice. If you crit, you get two more attacks. If they crit, you get two more attacks. I've seen a PC increase the crit to 8-20/x4.

This is why I don't allow Dragon Magazine in my game.