I wince at the thought, but is it possible, given a low enough temperature, for urine to freeze instantly into an icicle if you're caught short in Arctic conditions. If so, how cold would it have to be? and could it be dangerous for an intrepid explorer? 

I often drink some amount of tea while working (or not working) at the computer. I read and write for a long time (both work and leasure stuff), and then I start solving an online sudoku and I have to run to the toilet that very minute!

Can it be explained what psychological (not physiological, I suppose) mechanism stands behind this?

Has anyone else experienced a similar thing?

I have yet to find a person not affected in this way while drinking, and I can't put my finger on why it happens.

Alcohol as many people know inhibits ADH (Anti-Diuretic Hormone) in the Pituitary and makes you need to urinate more. Okay, fine... But why can people last for a few hours (well, a substantial amount of time at least) before urinating for the first time while drinking alcohol. But after urinating for the first time, the urge to go again comes incredibly quickly, hence the common colloquialism: "opening the floodgates".

Can anyone help to explain?

Are there any other foods which affect urine this way? And why do people often report not noticing the smell until someone else points it out?