Another Zaytinya near Dupont? No, it's definitely in Chinatown / Penn's Quarter. There are three exits to the Chinatown Gallery Place metro: one by the arch in Chinatown, one directly in front of Zaytinya, and one at the Verizon (still want to call it MCI!) Center. All the stops are within 2-3 blocks from each other. Jaleo and Zaytinya are within waling distance from each other. Both are fantastic tapas, but Jaleo is more traditional Spanish and Zaytinya is Mediterranean. Not coincidentally, they have the same owner: Jose Andres, who also owns Cafe Atlantico (also not far from Chinatown) and Oyamel.

For Dupont restaurants, I would second Pesce and also add Firefly, Bistrot du Coin, Pizza Paradiso, Komi (spendy), and Vidalia. My favorite ethnic food in the vicinity is Malaysia Kopitiam. For a fun experience, try a burger and the crazy huge beer menu at Brickskeller (although they're not as reliable as they used to be!) If you're just looking for a cool urban lounge to kick back with some drinks, again Firefly is a good choice in that vicinity, as are Topaz, Bar Rouge, Science Bar and Cloud. For more casual, hole in the wall type places, you could hit Lucky Bar, the Big Hunt, Buffalo Billiards, or Lucky Bar.

And I have to add, as someone who lives in Silver Spring and travels to Dupont all the time, if you were my friend, I might ask you to take Metro, too! It's only a twelve mile round trip, but between traffic lights, cars parked along 16th Street and people just driving like idiots, it can feel like forever, even barring traffic! I pretty much always take Metro...

Enjoy you're trip!