Hi Christopher,
You can run this query under Host/SQL:
select top(20) Users.FirstName, Users.LastName, Content, HtmlText.LastModifiedOnDate from HtmlText INNER JOIN Users ON HtmlText.LastModifiedByUserID = Users.UserID order by HtmlText.LastModifiedOnDate
It will give you the information for changes on the HTML module contents. But it will not cover all modules other modules. Each module tracks their changes on its own particular way. There is no general way to get that info for all kinds of modules.
Cheers,
Aderson