Update: Gene has confirmed that the LA event is not really fan-focused (No Party) as the San Diego Event..
SEGA has a lot of plans to celebrate the series anniversary and it seems plans extend past the upcoming event SEGA is holding in July. As stated in the above video, they are planning a major anniversary party down in LA and it will be held very close to the location where the E3 Expo resides.
Sonic Stadium’s Shadzter notes that the event may not necessarily be the major venue for the highly-anticipated announcement of Sonic’s 25th anniversary game, currently being developed by Sonic Team. (Waiting for confirmation from Shad himself)
Marlene Sharp, Producer, TV Series, Sonic, Sega of America took part in the above recorded debate about women in the film and television industry at The Digital Hollywood Experience event in LA. During the discussion Sharp (at 21:30) mentions that SEGA of America are in talks with YouTube Space LA to hold “a special Sonic the Hedgehog 25th Anniversary cocktail party or something like that.