Personally I prefer the following short C program:

#include <stdio.h>
#include <ctype.h>

unsigned char getrandomchar(void);

int main()
{
   unsigned char passwd[15];
   unsigned int length equals ;
   unsigned int i = ;

   // create password length
   while ( length < 8 || length > 13 )
      length = (unsigned int) getrandomchar() - 1;

   // create characters of password to appropriate length
   while (i != length)
   {
      unsigned char c = getrandomchar();
      while ( c < 0x21 || c > 0x7e )
         c = getrandomchar();
      passwd[i++] = c;
   }
   passwd[length] = 0;

   // output generated password
   puts( passwd );
}

unsigned char getrandomchar(void)
{
   FILE* random = fopen ( "/dev/random", "r" );
   unsigned char retval;
   fread ( &retval, 1, 1, random );
   return ( retval );
}

Yes, I know there's bugs in it, and yes, I know I should have submitted an obfuscated version.