MASN and my FIOS in arlington gets SNY too, unfortunately it's not HD, but I'll take what I can get.
As for bars, I second what ChampHusky said, Cap Louge or Hawk n Dove for capital hill places to go watch. Easter market there's Molly Malone's as well, not a great sports atmosphere but a solid brunch and you can def catch games on the TVs they have there.
The DC Alumni association has been holding their watches at Grand Slam sports bar in the downstairs of the Hyatt in downtown, haven't been paying attention if they've started up so far this year and the venue has changed a few times in recent years. If it's packed with UConn fans it's great, if not i wouldn't recommend it. Penn Quarter in Penn Quarter is cramped but will have every game you can imagine on, and also a plethora of other fans. I forget if it's dominated by a single school at the moment.
Avoid Carpool in arlington during Penn State games, or risk being killed to death by constant "We Are" chants. Otherwise, for any other game it's great, tons of tvs and good beers on tap.
Another dive right near the capital is Hamilton's, but that gets overrun by a few teams as well. Will be a good atmosphere though.