Implement:

* more distributions, see
  http://en.wikipedia.org/wiki/List_of_probability_distributions

* ISAAC generator
  http://burtleburtle.net/bob/rand/isaacafa.html

* TEA generator
  http://portal.acm.org/citation.cfm?id=1921500
  http://www.cs.umbc.edu/~olano/papers/GPUTEA.pdf
  http://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm

* prime moduli LCGs
  http://dx.doi.org/10.1016/j.cpc.2011.06.013

* take some ideas from
  http://www.thesalmons.org/john/random123/papers/random123sc11.pdf
  Parallel Random Numbers: As Easy as 1, 2, 3

* Intel hardware random number generators (RDRAND)

