tmk knowledge, there isn't a comprehensive thread on happy hours out there so i'll start one. pls forgive me if any of my info is inaccurate or out of date.

PORTLAND, OR
(i only start with portland because i'm here this week)
-henry's - 4-6 and 9- 11 daily; nice bar menu $2-$4
-portland city grill - 4-6 and 10-12 daily; ~same menu as henry's, but better classier
-mccorkmic & schmick - varies-6 and 9:30-12; harborside location is lousy, but oak st is nice (better menu/food)
-here's a sort of old article i found online with a few others: http://www.portlandmercury.com/2001-08-16/ex3.html

BALTIMORE
-mccormic & schmick - 3-6:30 and 9-12; one of the best happy hour menus i've ever seen at an m&s, but they often try to get away with canned oysters
-m&s grill - 3-6; preferable to its older cousin because of the ribs if you can off early enough
-hrc- 4-7; 1/2 priced apps and drink specials
-cvp- 4-7; 1/2 priced apps and drink specials (food is pretty bad, but if you're in charles village....)

WASHINGTON DC
-lots and lots to choose from and kind of complicated because different places go on different nights
-my favs are smith and wolly's, m&s (or course), that tequilla grill place down town, the luck bar, and the front page (actually, i don't like the front page, but it can be pretty fun, i guess)

BEIJING
lots of places have 2 for 1 drinks 5-8; some of my favorites
-shillers- the wheat beer is awesome
-jazzya- kick-... long islands
-susie wong's
-no name bar
as far as food specials are concerned, i only know of friday's which i don't like very much

SHANGHAI
-mural- my favorite 2-for-1 joint because i like their mojitos and it feels kind of like a cave
-face- sells certain drinks (none of the cool ones) at a 50% discount before 8
-long bar- not my scene, but during happy hour at least the drinks aren't too expensive
-all the mexican places have specials on tuesdays; zapata's is the most fun, but i warn you that the food is pretty terrible (good drinks though)

that's all the energy i have for now.