This is so painfully simple, you don't need to be adventurous or crafty!
Water stains are so irritating, especially on a nice piece of furniture. This is the most simple, permanent solution to get rid of them.
-Stained piece of furniture
-Dry dish towel/t-shirt/rag
Turn iron on low/medium heat.
Place towel over the stain.
Gently run the iron over the towel.
Voila! How easy was that??
I would also suggest a good oil or polish afterwards.