We're a little late with this news, but heck if it isn't worth posting about anyway. Sudoku 2.0 has been released for the PSP, just in time to sharpen up those brains of ours that have considerably dulled from all those shots of eggnog and saccharin sweet holiday cheer. If you haven't already been introduced to this addictive game from Japan, Sudoku is a puzzle game where you have to arrange the numbers 1 through 9 on a grid so that the same number doesn't repeat vertically or horizontally. It seems simple enough, that is until your hair falls out from trying to figure out the nth possible number combination in this sometimes maddening game. Here's a tip: break up the grid into 3x3 quadrants. It'll give you and your hairline a much-needed break.