The aftermath of the events at the Boston Marathon had me wanting to shut off my thoughts and the television and get lost in something mindless.  Luckily I had the perfect escape and I went to the final performance of the Pittsburgh Chamber Music Society 2012-13 Season.  The Ebène Quartet was playing last night at the Carnegie Music Hall connected to the Carnegie Museum of Pittsburgh in Oakland.  I love going to museums at night.  It brings out a giddy, imaginative, childish quality in me.  There is something that feels really sneaky about being in a museum after dark, like you may live out your childhood dream of being locked…