Here's one of Dave's masterpiece of a replica of the Genius Rock from Apollo 15 in exact detailing. I own this and man does it look like the real lunar rock.
Here's the ebay address for it.
Apollo Moon GENESIS ROCK Replica+Meteorite Scale Cube - eBay (item 330307482540 end time Feb-19-09 10:00:11 PST)
lox_501