Thanks for starting the thread: this is a huge deal in my family.
Starting with non-EU day, it looks like if you take the metro to Van Ness, you have the following embassies all open that are all more or less on the same block:
- China
- Bangladesh
- Singapore (this seems new for 2026?)
- Ethiopia
Then you have a bunch of countries that have just a table at UDC's student center, which is also right at Van Ness. We went to that last year and were really disappointed at how lame and poorly organized that was. But these Van Ness embassies are typically less crazy than the madness that happens on Mass Ave, though there's usually a protest or two outside the Chinese embassy. Nonetheless, given our kids recent interest in Ethiopian food we might go to Van Ness.
Another thing to watch out for is that some countries don't host this at their embassy, they host it either at a consulate or at a "cultural house" that they maintain somewhere in DC. These can be all the way on the other side of the District and they're not always great at noting this on the Embassy Open House website. For example Ukraine will almost certainly host things at Ukraine House in Kalorama, not at their embassy, and Mexico and Romania are frequent offenders of hosting at their consulate not their embassy, and Oman is always at the Sultan Qaboos Cultural Center.
Off Mass Ave, Ukraine House/Turkey/Belize form a possibly intriguing cluster, with Sri Lanka and Japan not far away. We had a great time at Sri Lanka's embassy in 2024 when they were giving away huge boxes of tea, which we just used up a few weeks ago.