Igotalife, how about some graffiti artwork for the skateboarding theme? You could also use half-pipe for something. What, I don't know! Maybe just as a chair rail?
Check out this site for more ideas: http://www.hgtv.com/hgtv/decorating/...633710,00.html
I also found this pic of skateboards being used as shelves like DesertRose mentioned.