Today I was reading a blog entry at jiujitsu365 about a new website called Fitocracy. It is a training log mixed with a competition mixed with social networking. You log your workouts and get points based on the different exercises. There are contests, quests, accomplishments and leader boards to compare yourself to other people. Since I am a competitive person, I can see myself really getting into this. If you need motivation to get in shape or lose some weight then this is the perfect site for you. Fitocracy also has groups so you can socialize with other people with similar interests.
If you sign up, I highly recommend changing your email settings because they are pretty spammy at first. Right now the website is in beta testing and is only available by invite. If you are interested in getting an invite, post a comment on this post, then email me at email@example.com and tell me why you deserve an invite. I have limited invites so I am not going to just post it here.