TAMSK
TAMSK is the second board game in the GIPF Project of six abstract strategy games, and was published in 1998. Players move sand hourglass timers and drop plastic rings around spaces on a hexagonal board in an attempt to limit their opponent's moves. Each player starts the game with 32 rings, and the player with the fewest remaining rings at the end of the game is the winner. The game is unique among the GIPF Project games in having time as a central game component, and the manner in which time is used is possibly unique among board games in general.
A timer must have sand running through it in order to be moved, and when it is moved, it is also turned over. Thus, rather than giving a set amount of time in which to make a move, each player's set of 3 timers all have variable amounts of time remaining in which they can be moved, and that time changes whenever a move is made. At any point during the game, it may be beneficial to delay moving or to move as quickly as possible, and an opponent can use another timer to force a move if it is in their interest. Timers that have run out cannot be moved for the remainder of the game.