Using online password crackers
Online password crackers are extremely popular and it's easy to see why. Instead of having to go through the trouble of cracking the password yourself, why don't you just submit it to someone else who has gigabytes, (to terabytes), of pre-calculated hashes to crack it for you. Just as a warning though, there are some privacy concerns when using these sites, (what? You don't think they store the hashes that are submitted to them?). According to www.hashkiller.com , which keeps track of the effectiveness of these sites, (quick disclaimer: recently the reporting mechanism seems to be having issues), most of these sites crack around 20 to 40% of the passwords submitted to them which is fairly good, (actually really good since most of them rely on quick lookups in pre-generated tables). This statistic matches what I've seen both from my own testing and looking at other people's results, (aka the person who attacked phpbb.com submitted some of the passwords to one of the