As far as i can remember, Coachellas i've been, the additions/surprises were:
05: Kanye West.
07: This year did't even need any.
09: M.I.A. (instead of Amy Winehouse, her visa was denied)
10: Atoms for Peace/Yorke-Flea-Godrich-Waronker-Refosco (Before they had that name, the lineup only announced "Thom Yorke ????")
11: Can't remember any, besides the Pure Filth's "Bass Oasis stage" inside the venue. (kick-ass performers, some of 'em even played twice)
12: 2pac's Hologram, Eminem, 50 cent, wiz Khalifa, among others from Dre's&Snoop's Crew.
Remember any other?
Who could be a Surprise based on this 2013 lineup?