Quantum Tic Tac Toe is a variant of Tic-Tac-Toe with "entangled" states (there are even iPhone and Android apps).
In essence, a classic naught or cross isn't placed until the 'quantum state' of the board is measured and forms a closed loop.
Here the pieces X3, X7 and O8 are measured when placing the two O8 pieces are placed and forms a closed loop:
Upon measurement, the player placing the X marks, picks whether O8 collapses onto square 3 or square 5. After picking, and resolving entanglement, the board looks like this (O2 and O4 collapse in 7, and 8 respectively. X5 to square 4.)
Is there a winning strategy for either player? If so, what is it? If not, how can one guarantee a tie?