Gamma Distribution

The gamma distribution contains two parameters and is related to the beta distribution, and is sometimes considered to be the generalized form of the chi-squared distribution. The most common sets of parameters are either: a shape parameter kappa and scale parameter theta, a shape parameter kappa and a rate parameter beta, or a mean parameter mu and shape parameter kappa. Skew is only dependent on the first parameter.
One of the most common uses of gamma distributions is modeling wait times (the length of time kappa it takes for n random event to occur), most notably for Poisson distributed curves. Another use is statistical analysis of probability density functions like those found in quantum mechanical wavefunctions.

Sources:
http://www.statlect.com/subon2/ucdgam1.htm
http://en.wikipedia.org/wiki/Gamma_distribution
http://www.math.uah.edu/stat/special/Gamma.html
http://www.stat.nthu.edu.tw/~swcheng/Teaching/math2810/lecture/05_ContinuousRV_1129.pdf