Real women have dirty houses
I don't trust people who claim to have clean houses, unless they have a maid. No working woman has a clean house--that's why we all dread the pop-in (or the, "honey, I forgot to mention that so-and-so was coming by"). If you do have a clean house, you can't be my friend because I'm insecure.
Here's my Martha Stuart Mask for pretending I keep a clean house:
Always keep Clorox wipes in the bathroom and kitchen. Clean only what is visible. You can use them on the floor too.
Always keep a large, empty tub in whatever room your guest will not be in. Before your guest arrives, run around the house and throw all your crap in it. If you don't have a dishwasher, keep another tub to throw dishes in (fill with some dishwater, don't be gross) for when you have the surprise guest on your doorstep. Put tubs back in the "hidden room" until guest leaves.
Candles, candles, candles--they make things seem cleaner. Stick with candles that smell like food (vanilla, buttercream, etc.). These are the best at masking the mess.
Try to have people over after dark--the house looks cleaner at night.
Since I've never actually managed to get the laundry cleaned and put away, make sure you keep all of your clean and dirty piles in the hidden room (or closet if you're short on space). Make sure the door to your hidden room is hard to open so that no one accidently goes in there.
It's O.K. to throw everything into trash bags and sort it out later. You can even hide the trash bags in the outside-trash bin. Just remember to go back out and get them when your guests leave.
Always get your guests drunk. They will be happy, and they won't remember as much.
I hope this helps.