Universal Studios Hollywood is hosting the Serenity Fan Fest this Saturday, September 24th from 2pm-4pm. Creator Joss Whedon and cast members Summer Glau (River Tam), Adam Baldwin (Jayne Cobb), Morena Baccarin (Inara Serra) will be there, along with special effects and prop exhibits.
It is free with regular admission, and all Browncoats get a discount. Serenity officially has its US open on the 30th.
Source: SciFi Storm