The sewer bar
Every bar in the world is unique: but few are as unique as Pai's "sewer bar". On the main street of Pai, they have a hilarious setup: the town's largest supermarket (not very large) is also the town's cheapest source of alcohol; and in order to cash in on this fact, they've got a long line of picnic tables and benches available right outside! So you can buy your booze for less, and not even have to worry about finding somewhere to drink it. There is one small catch — namely, the sewerage drain that runs uncovered down the side of the street, and that makes the picnic-bench area positively reek — but 'tis a small price to pay. And in my opinion (and if you have a different opinion, then you may kindly shove it up your a$$ :P), this only adds to the ambiance. There are some things you can only do in a small town in Thailand.