A clay pot in the episode "Committed". Crafted while two people were having an argument. Of course, the marks on the pot were vibrating to the argument. When the clay pot is analysed, they shoot a laser at it and get a sound back. Behold! It's the argument being played back - reproduced from the bumps and grooves made in the pot during the argument.Now, assuming this is accurate (and I did google it to see if other websites had the same info and found other references to it that didn't look like copies of the Wikipedia entries), this could lead to all kinds of fascinating discoveries. Imagine being able to listen to what the slaves and artisans in ancient times were saying around their drying clay pots, bricks, and ovens! Now that old line that goes something like 'the stories these walls could tell' can finally come true!
Of course, forensic filtering will probably have to be applied to reduce the effects of centuries of accumulated dust, grime, and cracks. Hmmm... That probably means hiss, muffling, and pops & clicks, as a minimum, but we've got filters for those - no problem!
If you need me, I'll be down at my local museum (after picking up a laser and an ancient languages scholar from the university on the way)...
(Image source: News in Science article on restoring ancient clay pots - also interesting reading)