Peg Solitaire

One board, a grid of holes filled with pegs except for a single gap, and one move available: jump a peg over an adjacent one into an empty hole, removing the peg you jumped. Do that enough times in the right order and you're left with one peg in the middle; get the order wrong and you end up stranded with pegs that can't move anywhere. It's a puzzle that's been worked out on paper and physical boards for centuries, and it holds up fine on a screen since the whole game is really just planning ahead.