I grind on NES Tetris nearly every day at speed 9, game-B. My personal goal is playing "perfect" games where only lines are used to complete rows. These games are by definition finite and sometimes end rather quickly given the nature of tetromino selection. When that gets boring I switch to speed 9, game-B at level 5 which is simply a battle for survival for 25 lines. This is a bit easier.

I will need to see how I fare against a newer version of the randomizer one of these days.