As an addendum to GoingAway's post, I have to catch a flight to SFO at 2:45 pm on Sunday, so will be going directly from brunch to IAD. If anyone else needs to head to IAD then, I can take up to two passengers. I expect to leave Harry's Tap Room around 1:00 pm, which will get me to IAD by 1:30 pm. If you have a flight before 2:20 pm or so, this might be cutting things too close for you.
Please send me a PM if you're interested.