A custom 404 error message! Actually it was just a 100% blank site before today.
To have a custom 404 you only need to create a file named .htaccess in the root folder on the FTP server and then add
ErrorDocument 404 /404.html
In fact I did that many weeks ago, but today I created that 404 file that gets displayed.
Try to go here: http://the-gamevault.com/thispagedoesnotexist.html! As you can see I have a button that simply takes you one step back in history....
< input type="button" name="back" value="Take me back" onclick="window.history.go(-1);" >
EDIT: I just discovered that you can actually use JS directly on the page:
EDIT: Try to click on this: Edit everything on this page! this enables you of editing the whole blog! try it out, you can click on any text on the page and then edit it.
Gives some possiblities!