(Side note: in practice, it's almost impossible to avoid the illegal side-channel communication of watching the other players get nervous as you start to do something stupid, so really the only rules-faithful way is to play over a computer.)

(Another side note: there's a game called The Mind[1] which is the board-game version of SleepSport -- the goal is to, without most kinds of communication, play cards from each players hand in increasing order. One way to win is to synchronize everyone's internal clock and play each card when that many seconds have passed.)

[1] https://boardgamegeek.com/boardgame/244992/mind

[2] https://stackoverflow.com/questions/6474318/what-is-the-time...