I'm not usually one to get a case of the Mondays, but if I do -- I definitely know where to go for a post-work cheering up: the Raw Bar @ Delphine, where every Monday from 5 to 10:30 p.m. they have an assortment of specials that's friendly for the palate & the wallet.
The specials include East Coast oysters for $1 and West Coast ones for $2 (seemingly nonsensical given the travel distance, but the Pacific oysters are considerably larger, meatier, sweeter and definitely worth the extra buck; don't believe me, just shell out the $3 and do a comparison yourself!)