All day Saturday Kelly was at a cup stacking tournament with my daughters, I was there by about 11 and we did not get out of there until about 5:30 or so, it was a long day, it was my younger daughters first time at a tournament she did not place but beat her old score so we were very proud of her for trying. My older daughter place 2nd place in an individual event for her age and 2nd place for a team relay event, it was good stuff. So you still ask what is cup stacking?
It looks like this is on fastforward but it is not, my older daughter does this in about 12 seconds which is still impressive.
This is the Speedstacks world record holder, I forget her age at the time though.