Sports that require artistic excellence, not just athletic ability. Often not considered sports because the are judged on art and not physical skills, sparts require artistic ability, and are judged. You cannot objectively say who is the best at any particular spart, rather who's form you like most. Often people can be very good at sports, but not at sparts as they lack the ability for the fine motor movements involved. Same with those who are good at sparts, they lack the speed or raw strength involved in many sports.
The word is based off of a combination of art and sport, because they are artsy sports. Judged on artistic quality and not physical ability.
Julie: Marching band is definately a sport.
Bob: Really, It's more of a spart. It's got this artsy thing going.