Visitors to The Museum of Modern Art in New York were treated to a special performance by actress Tilda Swinton yesterday, as the actress launched a month-long performance at the museum called The Maybe.  The artist spent the day sleeping in a glass case in the museum’s lobby, and will return to the case several times during the duration of the performance.  No one knows when Swinton will appear for her performances, emphasizing the unpredictability of the work.  “There is no published schedule for its appearance, no artist’s statement released, no museum statement beyond this brief context, no public profile or image issued,” MoMA stated in a press release. “Those who find it chance upon it for themselves, live and in real-shared-time: now we see it, now we don’t.”