The intelligent cup lid system that changes with color will tell you when your drink is hot enough.

The color-changing smart cup lid system is a lid designed specifically for your coffee or other hot beverages. When the coffee cools down, the surface color of the lid noticeably changes from an unsafe red to a more normal brownish hue. Another important feature of this product is that it can be used as a seal indicator, showing whether the lid is securely and tightly placed on the cup. Once, I grabbed my teacup and spilled it all over myself and my books because the tea was too hot. A recent issue of BusinessWeek 2.0 reported and ranked the "29 Best Inventions in the World."