Grassboarding is a sport that has been practised in Costa Rica since 1990. A patent was presented to the local Intellectual Property Office in 1995. It uses a special concave board designed for use over a grass hill.
It belongs to the same family as surfing, snowboarding and sand boarding. It doesn't use any wheels, which makes it different from skateboarding or all-terrain skate boarding (ATS) or mountain boarding.
References
Grassboarding Wikipedia(Text) CC BY-SA