A while back, I encrypted a few files with Truecrypt, and stored the password in my head. Now I need to access it again, the password isn't working. I'm sure most of it is right, but I'm off by one or two characters. Is there a program that will allow me to tell it most of the characters in the password in order, and guess the rest through brute force?
http://www.autohotkey.com/board/topic/86586-tcbrute-2-truecrypt-bruteforce-password-recovery/ seems like exactly what you're after.
The other one to try is OTFBrutusGUI - which can be had from http://www.tateu.net/software/ - though it has little documentation beyond scattered forum posts (such as http://www.tateu.net/forum/index.php and http://www.wilderssecurity.com/showthread.php?p=1834959).
More generally - John The Ripper (http://openwall.com/john/) is a generic brute-force tool often used and adapated to these sorts of scenarios. And TrueCrack (https://code.google.com/p/truecrack/) is specifically for missing TrueCrypt passwords. It goes almost without saying that these aren't effective at all against passwords you have no knowledge of (assuming a reasonable password strength).