Cheat Engine. A development environment focused on modding games and applications for personal use.
For the latest version:
For older versions, check out https://github.com/cheat-engine/cheat-engine/releases
The forum is up/down depending on DDoS attacks. In the chance it works, you can read posts at http://174.142.61.111/forum
Alternate websites: http://reddit.com/r/cheatengine
http://fearlessrevolution.com/index.php
You can also follow cheat engine on twitter: https://twitter.com/_cheatengine