After spending so much money on a cool coffee or kitchen table, it doesn't make much sense to put a 5-cent coaster down to protect it. Not to mention, why not sport a cool set of coasters that are conversation starters all by themselves. These eco-friendly water absorbing concrete coasters ($13) are made of non-toxic recycled cement and ash. Surprisingly they soak up quite a bit of water while looking cool and protecting your table.