As with my last car problem, this one occurred while my girlfriend was driving my car. Seriously, any time she takes the car somewhere something terrible happens and needs to be fixed. So far it's been a flat tire, she ran into a tree, and now the rear heat exhaust shield rusted off.
Now, while driving home she noticed a clear, odorless, and tasteless (I checked) liquid from underneath the driver's side dashboard right above where the pedals are. The liquid pretty well saturated the driver's side floor mat.
I'm pretty sure it's water and doing a little bit of research it appears that it could be related to the air conditioning system via condensation. My only concern was that it looked like a lot of water, like the whole floor mat is pretty wet. She told me it stopped when she turned off the air conditioning, but I couldn't get it to replicate by turning the air conditioner back on for 10 minutes or so.