LOLz – good one :lol:
It's all relative, though. For both Darts and snooker, you're still moving multiple muscles so at least it is SOME form of exertion.
I'm less clear on Chess (mental stimulation, sure, but you're only really moving one hand) and computer football (whatever you call FIFA...
Definition of sport is: 'an activity involving physical exertion and skill in which an individual or team competes against another or others for entertainment.'
Therefore, curling, darts, snooker, etc – all sports.