John the Ripper 1.6.39 Windows Build
John the Ripper, created by the folks at OpenWall is a powerful password tester (read: cracker). Their latest version (as of this entry) is 1.6.36. However, there only exists a UNIX distribution for it, and it lacks some major files. For people who only have access to Windows machines, use this distribution, especially compiled for Win32 and optimized for MMX-style architectures (if you've bought a computer in the last 7 years, this will work on it). Use this distro if you're cracking on windows, as you'll see 2-4x improvement on cracking speed. At least I did.