THat's got me thinking.... what would be cool is a door mat that when stepped on, blasted some dance music and flashed Dance Dance Revolution patterns!!
That reminds me of an idea I had thunk for one of my old apartments, to hide built-in DDR step controllers under the living-room carpet, and add a bunch of extra buttons all across the floor in a matrix just to trigger sounds; the stairs could have been the most fun.  I had a projector setup there and was trying to come up with an experimental audiovisual installation for entertainment.  It was just a dream project though, and I had 
enough too many real projects already.