LivingSocial is an app for Android smartphones that you can check for daily special deals and offers in your city.
Much like Groupon, the system works by businesses signing up to the service. Then LivingSocial forwards you a selection of deals every day, which you can take advantage of using the app. There are "escapes" for travel deals and "daily deals," which could be anything from a discounted price for club admission to a half-off Swedish massage. You can also take a look at and purchase deals directly from LivingSocial's site online.
If you sign up for a LivingSocial account you can email offers to your friends, and if three of them use your link to buy the deal, you get yours free. The app itself couldn't be simpler - the interface is a piece of cake to navigate, and is very attractive.
The downside of LivingSocial is simply that it doesn't cover all cities yet, although more are being added, including in Europe and other locations outside of North America. The other issue is that you are always restricted to the offers on LivingSocial for that day - there is no search, and you can't refine the kind of deals you want to receive.
If you're an avid bargain hunter, LivingSocial might just be the app for you.