We will be in Prague for a week the end of October and I have just discovered there is a National Holiday on October 28. Does anyone know how this holiday is celebrated and what it will mean for us in terms of closures? We had wanted to got to Plzen for a day trip by train so will not go that day if things are shut down.

Everything isn't shut down any more than in most countries country on their national day. It's their independence day (Independent Czechoslovak State Day). It's a nonworking day so people don't have to go to work in offices, banks, etc, and lots of shops are closed. Trains never shut down. I wouldn't expect it to affect the main sites that I presume you are going for -- the Great Synagogue, the cathedral, and the brewery museum.

In Prague, the President makes a speech (on TV), awards some medals to good citizens, and there is a big to-do at Prague Castle for the elite, you have to be invited.

I will be back in Prague over this period.Tas far as I am aware there will be a sunday transport service running which is pretty good.Getting to Plzen should be no problem.
Me I am going to see Viktoria Zizkov play football.