Write a polyglot (code that works in two or more languages) that has a "mid-section" that can be modified to do any computational task. This question is similar to http://stackoverflow.com/questions/1053931/code-golf-shortest-turing-complete-interpreter.
The program must be able to preform a computation and print the results. Pseudorandom number capability is a plus but not necessary. The results must be the same in all languages, minor string-formatting differences are OK.
There is a section in the program that can be modified (in a straight-forward way) to do any computation (Turing complete). This is like the "comments section" in http://ideology.com.au/polyglot/polyglot.txt for which any comment can be inserted.
You must use at least 2 languages (this rule is here so you don't sue me).
Edit: Ideally you only need to write the "computation" part once. It is less interesting to use comment blocks, etc to knock out A so you have a block from B and then knockout B to write code from A. However, the one block solution is very difficult unless the languages have enough "overlap".
Also, using very similar languages (like C# and Java) isn't as interesting. It is still allowed but will probably earn less votes.
The winning is a popularity contest (Mar 1st).