Yes Man, by Danny Wallace. (920.042 WALLACE)
The author was stuck in a prolonged mope (of a very British sort) until by chance he met a bearded man on a bus who suggested the following prescription for happiness: "Say yes more..." According to this fellow, opportunities for happiness come to people who are open to them. You never know what may come if you try something new.
Never one to do things by half, professional enthusiast Danny Wallace threw himself into the mission: until the end of the year he would say yes to every suggestion or direct question that came his way. Adventures and near-catastrophes ensue.
Travelogue, cautionary tale, love story, whatever: it's a delightfully loopy book. Wallace is charming, empathetic, and occasionally, simply pathetic. There seems to be a small but growing collection of books in the sub-genre of 'bar bets taken too far' (see Tony Hawks' 'Round Ireland with a Fridge'-- 914.15 HAWKS) but so far I haven't met one that failed to entertain. Maybe I'm just a sucker for that sort of thing.
Either way I highly recommend this one.
Tony Hawks' "Playing the Moldovans at Tennis" --947.608 HAWKS
and Wallace's other book "Join Me" --070.92 WALLACE