The Czech Republic is a member of the European Union since 2004 and member of the Schengen area, so from most of the European countries you will not need a passport. The official language is Czech, but a lot of the population speaks other languages as well. (The younger generation speaks mostly English, the older generation speaks mostly German.) Czech people are kind and helpful, and they are trying to help you even if they don’t speak the same language as you. :)
When traveling to the Czech Republic, you will have to be careful that even it's part of the EU, it is not part of the Euro-zone. The official currency is the Czech Crown (CZK). 1 EUR is ~27 CZK. In most of the shops you can use your credit card, but in the small ones it's not accepted, so we would recommend having some cash at hand.
Prague is the capital of the Czech Republic, with a population of 1,2 million people, and it is one of the most beautiful cities of Europe. It's named the city of a hundred spires, and by looking down from the Castle, you will understand why. ;)
Things you have to see in Prague: Old Town Square; Astronomical Clock, Prague Castle, Charles Bridge, Saint Vitus Cathedral, Saint George Convent, Golden Lane.
Euro 2016 will be the 7th Rubik's Cube European Championship, after 2004-Amsterdam; 2006-Paris; 2008-Bilbao; 2010-Budapest; 2012-Wroclaw and 2014-Roskilde. It's opened to any nationalities, but only competitors from European countries can win prizes and the European Champion title.
Euro 2016 is an official WCA competition, and the WCA Regulations will be followed. If you are not familiar with the Regulations, you can check it out here.
The violation of any of these regulations may result in the disqualification from the whole competition. By entering the venue, every participant accepts the rules of the competition.