you could make the "index.html" page that says the site is closed....
If you want to leave your site up but just make it appear that it is down I would copy the home (current index.html) page and name it something else like Home.html and then go back to the index.html page and say--Site closed or whatever...
If you want you stuff completely removed from the internet then I would guess you need to delete the site and/or save it for later....Not sure how to do that....
