Background is easy to change, Its just a css image linking to it, You can change by editing to a different background,
Remove "background-image: url(/images/jaja.png);" And edit /images/jaja.png to a different background!
Looks alright. Maintenance pages only need to be basic and straight to the point and you've achieved that in this design. Maybe you could add some place for a twitter/facebook box?
Okay
I don't like this, I decided to just add a widget for twitter, Without ending the box </div> so its all in one container, Don't know if it looks any good but here: