The web site is not that informative and does not include info on all of the spots right now, but the Vineyard is promoting its own Restaurant Week. Most of the places listed have been here a while, with the exception of The Blue Canoe, located in the old home of Mediterranean in VH.
Good chance to get out and try a place you've never been. Note that Sharky's price is for two people.
(Also, The Oyster Bar in OB is still promoting its special on oysters- $1 each Friday and Saturday evenings. Not sure how long that will last, so call ahead if you are visiting.)