Random number generator

  $$RAND.xxx

  Will supply you a random number from 0 to "xxx".

  ex: 
  > $$Rand.100 
    - will give you a random number from 0 to 100.

  Note that if you wanted a range of 1-100, you would have to do
  > x = $($$rand.99 + 1)

  You can also use a variable as the last part. This must be a
  simple variable - i.e. no variable paths, vars within vars etc.

  Ex:
  > var = 100
  > number = $$RAND.$var

  The function used to generate the number is SAS's drand48() which 
  generates the number using a linear congruential algorithm and 48bit 
  arithmetic... I don't know what it means, but it sure sounds good :)