As of early summer 2014, there aren't any smart contacts on the market, although some products are coming close. Google is apparently in talks with the Food and Drug Administration (FDA) on its glucose-sensing contacts, which could be a stepping stone for this project, as well as a boon to people with diabetes.
Another company, Innovega, demonstrated contact assisted augmented reality at CES 2014. Their special iOptik contacts provide different optic paths to work in conjunction with a pair of display glasses, but in that case, the actual computing hardware is in the glasses rather than the contacts.
If Google's image capturing contact lenses do come out, there are lots of possible applications. Google Glass has already been used by medical professionals and other emergency personnel to speedily access life-saving information, so one can imagine similar applications for this much less obtrusive tech [sources: Makarechi, Kelly]. The ability to blink commands, communicate with nearby devices and display information could make it a great hands-free way to get and send info while doing everyday things (hopefully not driving, of course).
Plus, anything that can do eye tracking, image interpretation and augmented reality display is bound to have fun gaming applications. That's something we can all get behind.