Call me crazy, but taking it back a step--In the time you've been in the home, how often has it rained as hard as it did when this happened? Also, as has been asked, is the floor cracked? If it is, are there any other cracked locations? Check those for any kind of pooling like this.
If it isn't cracked at all, check how close it is to a window. Could the fluid have dripped in through some kind of leak, there? If that's out of the question, then it has to be coming from inside the home. It doesn't make any sense for it to be coming from elsewhere if all those other factors line up in a negative.
I'm a security analyst for [URL="http://www.tnhomesecurity.com"]Guardian Security Systems[/URL] in Nashville, TN. That's about it.