Anyone know of an add-on to show when your website was last updated?

I love all the advice this group gives and I have learned alot from each blog.    

With our rules in Virginia cracking down on website management   and getting very strict on when was the last time you updated your website.  Plus showing on your website, the date you last updated.  I thought maybe some of you might know where I can get an attachment.  Sort of like the one that shows how many times your site has been visited.    

 Appreciate the help and advice.