I shuffle a deck of cards and deal them one by one, as slowly as you need me to. You observe the sequence of cards and at any point of your choosing you say Stop. I then deal the next card: if it's black, you win. If it's red, you lose. No jokers and no sleight-of-hand. If you fail to say Stop until the very end, the last card determines the outcome of the game.
Share the best strategy according to you in the comments.