- Fixed typos.

- Made the PHP script executable.

README.rst

 The prime benchmark
 ===================
 
-Bencmarking programming languages by running program to find the first X prime
+Benchmarking programming languages by running program to find the first X prime
 numbers. The algorithm is naive and should be implemented the same regardless of
 the language.
 
@@ -31,7 +31,7 @@ Test: ::
 History
 -------
 
-When starting to learn Lua, I wrote a simple program to excersize the table data
+When starting to learn Lua, I wrote a simple program to exercise the table data
 structure. But I had difficulties expressing what I wanted so I first wrote the
 program in Python. After I had the program written in both languages I did the
 obvious thing, I timed them. From there on Barak implemented the program in PHP

prime.php

+#!/usr/bin/env php
 <?php