To crack your passwords
I was reading Doc's recent post on passwords you shouldn't use, when I remembered this tool which calculates how long it would take to crack your password. It's safe to use, it was featured on gizmodo, and if you want to be reassured, read here. Some passwords only take a fraction of a second, and others can take years!
I have passwords ranging from 5 hours to 10 million years.
It's kind of a fun and useful tool to use, post your results if you want to share how good/bad your password is!