If you're a cheap-o like me, get a big piece of cardboard and head down to the river park by the aquarium. Carboard-sledding down that hill at the river is the best fun you and your kids will have all year. Parking is about $2-$5 depending on how long you stay.
I haven't heard of anyone trying to stop the sledding. I took my boys there this weekend, the hill was icy and people were cardboarding on that! My boys had a blast.
It doesn't appear to hurt the grass. I guess it just causes it to grow "down-hill" LOL...
Across from the aquarium there is a playground, the hill next to it. It is an absolute blast.
Someone told me there is another place to do it across the river, but I am not sure where it is.