The bigbox stores sell "stone" spray paint. A can costs between $6 and $12 usually. I like to mask off the edge of my basic snowboard helmet and paint it with this stuff. While I'm at it, I remove the lens and strap from my ski goggles and paint them to match my helmet.
One of these years I'm going to buy or make some foam "gravel" and glue some of that stuff on the helmet.
Enjoy the comments in the lift line since you'll be the only one with a rockhead helmet and matching goggles (well, maybe not now...).
Step 1: Shiny helmet
Ever wonder why helmets are shiny? Maybe so they'll skid better on asphalt and concrete and keep your neck from snapping?
I'm not too worried about my helmet "grabbing" the snow, but if you paint up your bike or skateboard helmet, you may wish you had left it slick.