Lambic is a style of beer that originates from Belgium. Spontaneous fermentation occurs on these beers with wild yeast and bacteria. Lambics are commonly dry, vinous, and cidery, with a slightly sour aftertaste.
Some folks make lambics at home using cultured commercially available yeast and bacteria culture.
Personally, I like Lambics very much. The ones I've tasted have all been unique and good to drink. I like blended lambics, such as Geuze, more than others since the complexities of the flavors is just awesome. Geuze is something I'll drink maybe once or twice a year, with some food that compliments it well.