Magical Tetris Challenge
Line Clear Graph
Here's a neat hidden feature for Magical Tetris Challenge's Endless Tetris Mode. Start a game in endless mode and tap A and B at the same time during gameplay. This will switch on a graphical display on the 2P screen that shows how many lines you have cleared (divided into singles, doubles, triples, and so on).
Credit Goes To: IGN 64

 Line Clear Graph