What's the name of the combination between a roller blade and a skateboard?

Question

So at San Francisco I saw a bunch of people carving on these weird skates. Each skate was a small square platform, like a piece of a skateboard deck, that you could fit one foot on, and on the bottom were two wheels adjusted like roller blade wheels. You stood your two feet on a pair of these skates and carved sideways in an S-pattern--the motion is closest to that of the Ripstik.

Answer 1

I saw these yesterday on Minuteman bike path in Lexington Mass.  They're called freeline skates.  You need good balance and some patience to elarn to ride them.