Drunken "cycling" (silly brit) is illegal, but probably not "as illegal" as driving (i suspect its punished a lot less harshly) and for good reason, it is not nearly as stupid. Drunken cycling at the worst will kill you and perhaps hurt a pedestrian badly, but that's only really reckless cycling, really the worst that's going to happen is you get run over, unfortunate but not really such a menace to society. Drunken driving on the other hand results in a whole lot more innocent deaths.

Having had my first semi-drunken biking experience recently i must say it wasn't that bad (despite being on a bike that was way too big for me and having not biked in half a dozen years (but as they say, its like riding a bike...)). I walked it the busy couple blocks and the rest was pretty easy. And the whole wooshing effect was pretty fun. (The story is that I was leaving a grad social and going to hang out at a friend's and someone else who was sober was driving someone's car so i had to take his bike.)