I've found the best deals on auctions ending on a weekend, Sunday especially. I think people zone out on the weekend auctions. Maybe they have more free time to bid while they are at work.
As a seller I am always amazed at the prices some of the junk I sell brings. People simply don't pay attention to what is on auction and average sale prices.
I was amused over the last couple weeks as I watched auctions and 'buy it nows' for the Cowon' iAudio X5 DAP. People were paying more for the unit than it was being sold for on the manufacturers web site with free shipping. Truely amazing how clueless some people are when at auction. I've seen the same behaviour at live auctions (police, estate, etc.).