I just dropped my Palm Pre in a sink full water and it lasted about 30 seconds before it turned off. I came back like 5 minutes later and noticed my trash can was glowing.
This time I grabbed my Evo and took a video of me putting the Pre back in the water. After about 2 minutes the backlight went out but the screen was still on, 30 seconds later it was still on.
The touchscreen is broken so I can't tell if anything actually functions, but screen is still getting power.
I just went back and looked at it and the backlight came back on.
10:57pm - Total Submerged Time: 20 minutes before it gasped it's last breath
Video is uploading to YouTube right now.
Edit: Just noticed that the time hasn't changed on the Pre, so it is still on, but frozen.
Part One: http://www.youtube.com/watch?v=wxJKf_iYGew
Part Two: http://www.youtube.com/watch?v=WxDpf587uxw