Last quarter, I've been on a soccer team which was playing indoors, but this quarter we didn't have enough players so I am on another one (and maybe next quarter I'll play for both ;)). This team ("physics force" :)) plays on Astroturf outside. And this artificial grass is really different!

When you fall down you can't really scratch your knee because it's so soft (it still hurts though ;)). There's not only green artificial grass, there are small black beads between the blades; I couldn't find out what the role of the black particles is, but they seem to fill up the space between the blades to make everything still a bit softer. Every time the ball bounces, it briefly leaves a black trace in the air - those are the small black particles (it looks a bit irritating).

Coming home, I had to pour out the black beads from my shoes! They were everywhere...