I think that when you make glass bottles, you can break a wood or stone brick with one. But if you do, the wood or stone brick will not break, but the glass bottle will break into pieces and you can hold the bottle and use it as a temporary sword. It only lasts 20 hits, though. It can deal 1-2 hearts (3.5 if crit). Note: This only works with Wooden planks and Stone. (Yes, cobblestone too.)
Basicaly any mob or player you hit.