Gertrude's at the BMA has Tuesdays with Gertie - $10 entrees and discounts on selected wines by the glass.
Helen's Garden in Canton has a 3-course wine tasting menu for $29 on Tuesdays and something else on Wednesdays (can't remember the details?)
Taste at Belvedere Square has 2 for 1 selected menu items on Tuesdays and Prix Fixe Thursdays for $30.
Are there any other midweek "specials" at places in/around Baltimore? Any type of cuisine (except chain restaurants) is ok.