I'll be in DC in a couple weeks and would love to pick up some doubles games. Is it hard to find a partner at thd courts? Are there any other groups playing pick up sand doubles?

Doubles is super easy to call next on. Watch the 3 mens/coed courts to see which is more suited to your level and call next. Weeknights players show up by 5pm and weekends there are players basically all day, but more in the morning.

People play doubles and 4v4. It would be easier for you to jump in a 4v4 game since there are more courts and people rarely come with a full 4 squad, but if you're willing to wait, you can call next in doubles as well.