I know there have already been so many ideas. I didn't go through them all cause I'm at work...sorry if something similar has already been stated but here goes.
I was at a ladies house who had lots and lots of doilies and similar lacework around her house, but her most intresting thing was a wall hanging that was made out of bottlecaps that were covered with crocheted embriodery floss and bunched together like grapes, they had little crocheted leaves on top too.
It was pretty cute and I haven't seen anything like it anywhere else.
Hope that gives you an idea