Here are a few examples of searches which need to be further tuned.

PHP
http://google.com/codesearch?hl=en&lr=&q=echo.*\$_(GET|POST).*
http://www.google.com/codesearch?hl=en&lr=&q=SELECT+\*+FROM+'\.\$_GET

Python
http://www.google.com/codesearch?hl=en&lr=&q=eval+lang:python&sbtn=Search

Java
http://www.google.com/codesearch?hl=en&lr=&q=.*executeQuery.*getParameter.*
http://www.google.com/codesearch?hl=en&lr=&q=%3C%25%3D.*getParameter*
http://www.google.com/codesearch?hl=en&lr=&q=%22%3C%3D+65553%22&btnG=Search

Perl
http://www.google.com/codesearch?hl=en&lr=&q=0xfffffff[^0-9a-f]&btnG=Search

C
http://google.com/codesearch?hl=en&num=0&sa=N&filter=0&q=%22strcpy(%22&ct=rr&cs_r=broken_re
http://google.com/codesearch?hl=en&num=1953392943&sa=N&filter=0&q=%22strcpy(buf%22&ct=rr&cs_r=broken_re
http://www.google.com/codesearch?hl=en&lr=&q=\[sizeof\(.*\)\]\+*%3D\+*'%3F\\%3F0'%3F;$&btnG=Search
http://www.google.com/codesearch?hl=en&lr=&q=^[\+\t]*printf\(getenv&btnG=Search
http://www.google.com/codesearch?hl=en&lr=&q=%22if+(errno+%3D+E%22&btnG=Search
http://www.google.com/codesearch?hl=en&lr=&q=getopt%20+%20%20%20argc%20%...