I am going to do this to my stairs:
Or maybe a little less colorful, like this:
See royaldesignstudio.com for inspiration.
I haven't yet settled on the color scheme, but I am leaning toward jewel tone gloss colors on black. Or maybe on cream, since the walls are tan.
I've bought some stencils, five different Moroccan tile patterns, more geometric than the ones shown here. (Search for "(moroccan,geometric) stencil" on eBay; yes include the parentheses, not the quotation marks. You can find the stencils in online retail stores, too, with a better selection depending on what you're looking for, but you also pay more. Like two to three times more. My cheap is showing here.)
(I've got my eye out for a beat-up chest of drawers that needs painting. Can you see the drawers decorated like this?)
They recommend that you cut 1/4 inch plywood to size, paint, then apply the strips to the risers with finishing nails or small screws or glue. I plan to use theatrical canvas, sized, painted, and applied like wallpaper, because it will be easier to cut, and leave more room on the tread.