I dont think this should go into Showcase because its nothing special…
Its just a test of my php and thinking skills.
You can register at the beggining. The details are sent to a mysql db. Then checks if the username has already been taken.
Login page. you can login here. If its incorrect it tells you. Bypass filter installed 
Try it.
register: http://register.chrisphp.com
login: http://register.chrisphp.com/login.php
try the bypass filter: http://register.chrisphp.com/in.php
If the bypass filter fails on you please let me know ASAP