Replying to Neighbourhood park

i want to set up a little park ever since i got back into skiing(yesterday). i don't really have a place, cuz the tobogganing hill by my house isn't very steep so little speed. i guess i could use my roof, seeing as how it makes an A shape at around 30-50 degrees of incline. i want a way to get some speed and set up a box or rail so i can practice with out having to drive over an hour to go skiing. any ideas? p.s. my street is like 10 degrees of incline, i can get speed, but i lose it very quickly. me and my friends built a jump before but it wasn't amazing.