Grass skis
1966
Grass skiing was originally developed as a new way for alpine skiers to train during summer. These short skis used rolling treads or wheels, which made it hard to control speed, and stopping was nearly impossible, a huge problem as falling on grass is nothing like falling on snow. Grass isn't smooth and is full of rocks and twigs; falling on grass hurts. Another obstacle for the sport was that the skis had to be cleaned and oiled after every use. They never became popular.