this is a list of the strongest beers in the world. Most of them will exceed 14% ABV.
http://beeradvocate.com/top_beers.php?id=abv
As people have pointed out there are a lot of belgian beers that have high alcohol. Another style of beer that typically has high alcohol content is the Imperial Stout. These are generally very rich in flavor and the high alcohol content isn't really noticable. However, because they are so rich in flavor they are very heavy and you really can't, or shouldn't, drink more than a few.
A lot of the big, high alcohol beers are too much for people. They have to have a lot of flavor to overcome the alcohol taste. If you're looking to try one of these higher ABV beers start with a belgian like Chimay or Duvel. Neither one is out of control in regards to ABV and both of them taste wonderful.