Convert Fractran into Brainfuck
Python, 182 chars

Option 1, standard byte cells.  There are only 255 possible inputs (0 as an input doesn't really make sense), so I just run a Fractran interpreter 255 times in Python and generate a simple table lookup Brainfuck program encoding the results.

import sys
I=map(eval,sys.stdin)
P='+&gt;,'
Q=''
for i in range(1,256):
 while i:j=i;i=([i*x/y for x,y in I if i%y==0]+[0])[0]
 r=j&amp;255;P+='-[';Q=']&lt;[-'+'+'*r+'.'+'-'*r+']&gt;'+Q
print P+Q


Output for the example input (___ = 246 more nested conditions, I can't paste the whole result as it is too large):

+&gt;,-[-[-[-[-[-[-[-[___]&lt;[-+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.-------------------------------------------------------------------------------------------------------------------------------------------------------------------------]&gt;]&lt;[-+++++++++++++.-------------]&gt;]&lt;[-+++++++++++++.-------------]&gt;]&lt;[-+.-]&gt;]&lt;[-+++++++++++++.-------------]&gt;]&lt;[-+++++++++++++.-------------]&gt;]&lt;[-+++++++++++++.-------------]&gt;]&lt;[-+.-]&gt;