Last weekend's project - made my crossover go from homely to handsome with a sweet walnut enclosure. Pretty nerdtastic, but my receiver is old and doesn't have a subwoofer-out, so I run the signal though the crossover first, and that sends the lows to the subwoofer and everything else back to the receiver to go to the main speakers. The walnut's not resting on the surface - there's about 1mm of space - small rubber feet are underneath. See what I did there? It's not too deep, so made the walnut rails and a plywood top to support the receiver in the back.