There was an ice rink on the car park over the weekend. I didn't go on but I'm told that it wasn't really ice. In fact, I've found the Wikipedia page for "synthetic ice" http://en.wikipedia.org/wiki/Synthetic_ice The Physics issue will be that the surface has a low coefficient of friction. The skates have a very small surface area and a polished metal surface also has a low coefficient of friction. If it had been real ice I could have written about the high pressure under the blade causing the ice to melt and you sliding along on a sheen of water which refreezes behind you.
