Nascar
Pool
Darts
Poker
Chess
To me, the difference between a game and a sport is the physical component, and I think Nascar is the most physically demanding of these 5 activities. The drivers' endurance is more taxed in a Nascar race than a pool player's body is taxed, even during a long set, in my opinion. The muscles that tire in pool are only the muscles that hold you in your stance; it's basically as physically taxing as standing in one position. Darts is even easier, with the standing being in a more natural position, and in poker and chess, you play seated.
Beyond endurance and muscular exertion, pool is more physical than darts because there's more movement in the game, and almost anything is more physical than cards/board games. Between chess and poker, poker is more physical, since posture and expression are physical attributes that can affect the game. Does anything physical affect the game of chess? Seems purely mental to me.
-Andrew