Step 1: Go to Mario's Puzzle Party (In puzzle) mode

Step 2: Go as far as you can (You dont have to, but if you dont it will take a lot longer)

Step 3: When you lose, and it goes back to the Puzzle Party screen and says 'Continue?', choose yes. You will be on the level you lost on, but with zero points.

Step 4: Let the game sit and watch as the blocks stack up side-by-side, dissapearing often. Repeat steps 3 and 4 as many time as needed to get to level 99.

Step 5: Just like step four, let your game sit, but dont touch the buttons, watch the blocks speed to the bottom of the screen.

Step 6: Wait until you lose, which may be soon, if so, press continue after earning your points.

You may get a lot of points, but you may get very little. While letting the game sit, I got 4800 as my high score, which will earn you 100 MP points.