Tracking ones sports activities is now possible via Nokia Sports Tracker. I am not saying that one would not been able to track his/hers own sports before, it is just that now it is doable almost in that way that I was hoping to be a year ago.
It is even possible to track the hear beat rate, but currently it seems to be only via Nokia N79 with Polar sensor belt. Perhaps soon bluetooth connection could be available in between any phone and a hear beat sensor belt. This would enable to track ones beats in a certain spot on the track. Thus someone else could track it too if this someone has no life.
Having such service available, enables some further creativity, as here in the Elf shape.