The quiet of a museum lends itself to all manner of pondering. What is this painting about? What WAS the artist thinking? For that matter, what is the museum guard thinking, stationed on the periphery of the room, Sphinx-like or perhaps merely bored? One might even pause to reflect upon the very idea of a museum, the rooms teeming with paintings and sculpture. Is this the only way to present art? Does it exist exclusively, or mainly within the respectable box of the institution? If you happen to find yourself in Florence's Uffizi Gallery, you may wonder what the appreciation of art has to do with gallop and shriek of hordes of Italian schoolchildren tearing through the rooms, oblivious to poor Botticelli, Leonardo and the rest. But that's a consideration for another time and place. It is in Vienna's Kunsthistorisches Museum that the pondering begins in Jem Cohen's Museum Hours . There we meet museum guard Johann (Bobby Sommer) and visitor Anne (Mary