Genius!
It's called the FoamAroma lid (http://foamaroma.com) was invented by Craig Bailey, who found himself unemployed and decided to develop this little brainstorm.
He fooled around with it in his kitchen, tesitng liquid movement in the cup (it slants to prevent the "geyser effect"). He even used a different material, so the lids can be reused.
Now he holds the patent. Four million sold last year at one-cent each. He makes them in America-- Florida, to be exact.
Interesting side note: Craig Bailey noticed that baristas and coffee shop owners drank from ceramic cups--they didn't even know that lids varied and could dribble and annoy. They never used them!
