Read through the last month's worth of questions about water in a basement or crawlspace - there are a number of responses discussing possible sources and fixes.
If you have pets or children in the house make sure it was not a kid playing with water, or an accident. That is a common cause of unexplained puddles on floors.
The key is to find the trail of lime deposits it left if it came in over the basement foundation (under the house wall), in the windows, through the foundation wall, etc. There should be some sort of staining, or a dark edge or clumping of dust as the water passed through it. To detect it next time, you could actually scatter some household dust around for the water to leave a trace in.
If you find no source, thoroughly wipe and dry the concrete slab, including using a hair dryer or fan to dry it so it turns light colored again. Then look every hour or so to see if a damp spot appears, indicating it is coming up through the slab. If so, this would be from water accumulating outside the foundation, or from a leaking pipe under the slab.
If this is the first time, look where it occurred. Look overhead for pipes - look for water ddrips or discoloration on water pipes, run water in a sink or tub to look for leaking sewer pipes, etc. If hear a window, could it have been rainwater (or sprinkler water or kids playing with a hose) blowing into and open window or against a window whose seal is bad and let the water in, or rainwater piling up in a window well and coming in under the window frame ?
If near the wall, check outside that area for water from a sump pump, gutter blockage, broken or misaimed lawn watering system, leaking hose or hose faucet, or downspout accumulating against the foundation.
If there were puddles several places but only around the perimeter of the slab, was it right after a very heavy rain, so could have been surface or roof water runoff ponding along the foundation, making its way down the foundation to its bottom, then popping back up at the joint between foundation and slab ?
If no go on all these, you may have to just wait till it happens again and trace it while it is still wet, thinking at that time of anything unusual that could have caused it.
If it happens again, feel free to use Submit Answer (below, yellow button) to provide more info on this thread, if you want more detailed and to-the-cause advice.