I was given one of those for Christmas last year, and I love it. It’s both beautiful and practical, in a very Scandinavian kind of way. Cups vary in size (8-9cm in diameter and 5-6cm high is about the norm), but all are very light – they weigh around 100g. Made of oiled wood, usually birch, the cups are cut out from one single piece, and can easily be washed with a bit of water (no detergent). They originally came from Lapland, where they are known as kuksa, although most Norwegians refer to them as turkopp (tour cup) or trekopp (wooden cup). Some have two, instead of one (or no), finger holes, and/or a leather string so that they can be tied onto a rucksack. Cheap they ain’t – expect to pay up to 200Kr in a specialist shop, although I’ve seen some on sale on the internet for less than half that price. So shop around.
See www.eagleproducts.no/hXGXzohdLG4h.16.idium (Norwegian only) to see a sample of cups – their articles are available in many sports shops.
Or (why not indeed if you have a bit of time on your hands) – make your own!… Follow the step-by-step instructions at www.bushcraft.ridgeonnet.com/Kuksa%20tutorial.htm