The kurtosis value describes the peakedness of a distribution. Sharply peaked distributions have positive kurtosis (kurtosis > 0) and are called leptokurtic. Flatter than normal distributions have negative kurtosis (kurtosis < 0), also called platykurtic. A normal distribution has a kurtosis = 0 and it is called mesokurtic.
Examples of Leptokurtic distribution:
Examples of Mesokurtic distribution:
Family of Normal distributions
Examples of Platykurtic distribution:
Uniform (continuous or discrete)
NIST Statistics Handbook: Measures of Skewness and Kertosis - http://www.itl.nist.gov/div898/handbook/eda/section3/eda35b.htm