Tokyo Big Sight recently hosted the annual Tokyo Annual Fair, or TAF for short, which ran between March 21st to the 24th. This is actually one of the largest anime trade fairs in the world which sees the first two days being for the press and anime industry members only and the other two days open to the public, much like the Tokyo Game Show.
The anime companies in attendance were many and varied, some of the ones at the show with their latest wares were Sunrise (Gundam, Tiger & Bunny), Toei animation (One Piece, Dragon Ball Z, PreCure), Studio Pierrot (NARUTO), Gainax (Gurren Lagann) and TMS Entertainment (Detective Conan).
EDIT: Part 2, the cosplay feature at the Tokyo Anime Fair 2013 is here.
The pics below were taken on the last day by Mikikazu Komatsu.