google codesearch is sweet. you can find keygens,vulgar words
and also many exploitable code lines. just try this:
lang:php eval\(.*?\$_POST
lang:php eval\(.*?\$_GET
lang:php eval\(.*?\$_REQUEST
lang:php include\(.*?\$_POST
lang:php include\(.*?\$_GET
lang:php include\(.*?\$_REQUEST
lang:php include_once\(.*?\$_POST
lang:php include_once\(.*?\$_GET
lang:php include_once\(.*?\$_REQUEST
lang:php require\(.*?\$_POST
lang:php require\(.*?\$_GET
lang:php require\(.*?\$_REQUEST
lang:php require_once\(.*?\$_POST
lang:php require_once\(.*?\$_GET
lang:php require_once\(.*?\$_REQUEST

you don’t know what eval include or require does??? try google.com