A high-quality modern recording of a core piece of the piano repertoire? Completely free? Legally?
Be honest - who's put a pencil into a grand piano, just to see what it sounds like? This clip is great. See a pianist preparing a piano, experimenting with new sounds from everyday objects, and improvising a short piece on his brand new instrument. (Please note: he's careful about where he puts the duct tape! Putting anything with glue into a piano isn't something you should try without knowing what you're doing and being sure it won't do any harm...)