No cup is spill proof, but this one looks pretty darn close.
Unbox Therapy took a hard look (and a few swings) at a cup that claims to be un-spillable. Maybe the right word is un-tippable though, because he takes some pretty aggressive swings at this cool device and can't get it to fall over.
The device has a powerful suction/air-tight seal system at the bottom that lets you pick the cup/glass/mug up without yanking it free, but keeps stray elbows and clumsy shuffles from ruining the party (or the work day).
If you've ever had to lay a stack of papers out in the sun to dry coffee spills, you know why this is a world-changing innovation.