I and my husband finally got to experience this tour event (2015). The fact is that previously, we booked a schedule via Rill's Bus Service, but unfortunately we both got ill after we arrived from our vacation in the Philippines...so, we had to cancel it! :(.
Around the World Embassy Tour happens every first Saturday of May yearly wherein at least 40 participating embassies open their doors to the public showcasing their culture, art, food and exhibits. This is a signature event supported by Passport DC and a part of Cultural Tourism DC project.
It's a once a year experience to take the chance and visit popular embassy open houses and witness street dance performances and exhibitions in the nation's capital.
The tour includes giving visitors a "Passport DC Souvenir Passport" to be stamped at each embassy they visit. Take note: passports are NOT free and cost $5. each. They can be bought at any available info booths in the area. They are not official passports by the way. I call them "toy passports", - only for the tour, used as remembrance. ;)
The tour starts promptly at 10AM and ends exactly at 4PM. Judging by the time length given, it is impossible to visit ALL participating embassies...perhaps one of the reasons why this event is being held every year to give ample time for visitors to complete their visits.
If you are visiting, an itinerary plan is highly recommended as to where to go first and where to go last due to time constraints. The only challenge in this tour would be waiting in long lines. Some embassies have short lines and nothing at all! Usually smaller embassies are the ones which are easy to access right away.
Brochure maps are available for free which are of good help too!
You can only get around by walking and by metro bus. Buses are readily available in some designated pick up spots which are all printed in the brochure with instructions. If you are very familiar within the DC area, you'll probably don't have any problem where to go and how to go around. Hassle-free!...except for long lines!