The 52nd Sakura Matsuri – Japanese Street Festival is the place to be on Saturday, April 14 for all things Japanese following the Parade until 6:00pm. The festival covers 6 blocks on Pennsylvania Avenue, NW. Cosplay is encouraged! For 21+ there are beer tents. For less, there is a ton of Ramune! (Last year's evidence: http://youtu.be/t5VKVylNj3M )
More information: http://www.nationalcherryblossomfestival.org/2012/04/12/enjoy-the-sakura-matsuri-japanese-street-festival-after-the-parade/
Browse the festival program for more information on:
Arts and Culture
A Taste of Japan
Please consider pre-purchasing an admission ticket for $5 if you are able to buy online and print the confirmation bar code page. While there are times that pay-at-the-door lines are short, other times it can be over half an hour long. A pre-purchased and printed admission will allow you to walk in at any time.
Also, be sure to get phone/text/twitter information from anyone you want to find, or set fixed meeting times and locations. The festival is huge and packed with people. There is also the possibility that the group will split up at times for food/drink/shows/etc. And remember, if at any time you need to step outside the festival gates, make sure to get a stamp so you can get back in!