Further to my tip below
about chilled water www.b3ta.com/questions/toptips/post772200, a word of warning. If doing this in a standard tumbler rather than a water bottle, don't use too much ice. You'll be swigging off the ice-cold water and be tipping the glass up further and further. But there's the risk that the ice will wedge in the bottom of the glass and water will build up behind it like some sort of micro-glacial lake. As you tip the glass up to get what you think is the last of the water, the ice will dislodge and the rest of the very cold water will tip over your chin, down your neck and down the inside of your shirt onto your chest.

This will take you by surprise and you will squeal like a big girl
( sandettie light vessel automatic New Twitter - @bollocksreally, Fri 9 Jul 2010, 17:40, Reply)