Replying to Material for summer jib

I am sure that all of you want to ski all summer long like myself. I've been thinking of ways I can make a jib in my back yard. My idea is that I will have a flat 1'1/2" platform 5' off the ground, followed by a 8' long ramp and a flat 1'1/2" long lip that is one foot off the ground. I'm not worried about what I'm going to make the ramp out of (wood seems like the best thing). What I need to know is what would be the best material to use to slide on. I do have access to snow through the summer, however it's a pain to get. I have thought of lying PBC close together perpendicular to the sides of the ramp, but that will most likely get expensive. I have also thought of using Astroturf and that black mat that you put on gardens to keep the weeds out. Do you have any suggestions or ideas? Oh, and if any of your ideas involve it I have access to power tools and I can weld.