It's the A/C drain pipe...
The A/C removes heat and humidity, (hence air CONDITIONING, not air cooler), and it does this by passing hot, humid air over coils that contain compressed liquid refrigerant, which remove the heat and humidity from the air... There is condensation from the water molecules in the hot, humid air, that usually escape out the bottom of the car thru the drain pipe...
Yours is clogged/disconnected...
As for the mist coming out of the dash?? hopefully for your sake it's not refrigerant escaping...
later

 

Wow, almost 2 years later now.. just an update about this A/C problem of mine since I originally posted.

Giving that tube a squeeze once every 6-8 months or so worked for awhile, but this spring it wasn't helping anymore. Maybe it got backed up in the hose further up than previously.. not sure. I had a mechanic try blow it out as a quick fix, but that only worked for a day or two. So then I had him take the hose out and snake/clean it. (Also got an A/C recharge too..)

Since then the problem hasn't occurred.. and I also stopped getting mist through my vents.