I hadn't even heard the race was last weekend, let alone who one, if anyone. Throughout most of the world the Indy 500 is considered to be a very boring style of race, essentially only watched or cared about in America. It's certainly not considered a "world" event.
I'm with Bebelamar, I found the movie to be quite boring. Long, long, long special effects shots that never seemed to end and didn't do anything for the movie.
The only close view you get of the cathedral is from the rear by/on the river, every other angle you're hemmed in by buildings so it will be difficult getting a full shot of it. If you're not afraid of heights and your knees can handle it, be sure to climb the steeple. There are actually two but you're on;t allowed up the left hand one. Wonderful views of the Flying Butresses and gargoyles etc.
Clarification: The building is actually Municipal House. Pragues principal concert hall is called Smetana Hall and is inside the building but it isnt an opera hall. There are actually three different Opera houses in Prague. The Karlin, National and Estates Theatres.
If you may have noticed, the sea level rises more in the summer than the winter. That's because of all the overweight people who swim in the ocean and therefore make the water level rise. If everyone lost weight before they went to the beach then the ocean levels would go down.
It's a huge park but unless you plan on canoeing, there isn't a great deal to do there. It is a wilderness park, not much in the way of facilities. There are a number of Interpretive Trails to take but they are relatively short, well under a mile, usually.