Thats g8 yarr! 1st You chk for traffic that frm where it come. What u did before a day to increase your traffic. Acctually this not happend suddenly without any work. so just careful. And let me know hows this happend. I m waiting......
If you have analytics you can see exactly where your traffic comes from. So just check out the reffering sites man!!
Mostly direct traffic in a day well it is possible only with some kind of offline promotion like newspaper and magazine promotion etc. If you haven't done anything like that then you are a magician and we want nothing to do with you... Brother that kind of traffic is simply not possible