In Brogue, some random numbers are generated with 'clumping'. Clumping basically means roll Nd(max-min) dice and then divide the total you get by N such that the random number is still generated in the same range, but with a bias towards the middle that grows the higher clumping is.
When clumping is < 2, the distribution is linear.
When clumping is 2, the distribution is a triangle.
When clumping is 3, the distribution starts to look like a normal distribution, and so on for 4 and above.