What is the half life of alcohol?

I asked Josh this question last night. Still feeling stupid for doing so. What I really wanted to know was how long it would take for the alcohol in Hooch (250ml, 5% alcohol) to be metabolised, so I would know how long I would have to stay in the pub before driving home.

Too bad I didn't get the answer I was looking for, so I didn't dare drink (I've since checked my PCL notes and found that 1-2 standard drinks will be metabolised in 2-3hrs.)

A few hrs later, I found myself lost driving along Bedok Reservior Road. Haha, missed the turn into Eunos Link. The reservoir looked creepy at 3am. It didn't help that I grew up reading Russel Lee ghost stories about drivers feeling as though they've run over something in the wee hours of the morning and getting out of their cars to find a boy under their cars offering them his intestines. Urgh.