James Burgess has designed a cup meant as a fake! Made from double-walled porcelain and a silicone lid, it works well to spoof onlookers.
I purchased one from the MOMA store. Although it feels a bit heavy, I look forward to it keeping my coffee warm.
UPDATE: It does keep my coffee warm, but the lid smells bizarre and stains. Maybe I am the one being fooled!
UPDATE #2: The cup is a nice concept, but it is no longer white. The lid is stained (from coffee & lipstick), and the cup's sides are stained from charcoal at my workplace.
Image source: momastore.org