Oh, the disappointment! I was going to have a big day of Mucha--museum on Panska is lovely--then I fought my way through the smelly beggars at Namesty Republiky metro to get a ticket, made sense of the metro system then walked several blocks to the National Gallery only to see the dreaded "temporarily closed" next to the Slav Epic details, something about falling plaster, maybe re-opened by August. It's still a great museum with plenty to make the trip worthwhile--Klimt, Schiele, huge wing of French artists and lots of Czech, of course.
We had the same experience!
Estimated date of reopening is August 1, 2015.
Website for updates is
Plaster fallen from ceilings. They are checking structure,
Oh wow, bummer. Thank you for alerting us of this closure!