Pretty much everything Tilda Swinton does is great, so when she showed up to sleep alongside a jug of water on a mattress in a glass box at MoMA on Friday, she immediately became the best thing in sleeping art since Andy Warhol's never-ending Sleep film. "Museum staff doesn't know she's coming until the day of, but she's here today," a museum source told Gothamist (who also took some fun photos.) The performance, titled The Maybe, will remain "unannounced" and "random" and will last for a full day when it happens. Swinton (who's done this before in London and Rome) hasn't said anything about the piece, and MoMA's official comments only confirmed that there would be "no published schedule for its appearance, no artist's statement released, no museum statement beyond this brief context, no public profile or image issued. Those who find it chance upon it for themselves, live and in real — shared — time: now we see it, now we don't." This sounds truly magical.