Take a rest! That is, go to Bratislava to get away from the stress of big city Europe and spend two days exploring small city Europe. It's clean, the people are nice, has plenty of history and culture, and, it has enough to do for two days and one night.
Where To Stay
Obchodna Street with it's views of Bratislava Castle
This is really important. Obchodná street is in the heart of Bratislava and will make walking around the downtown area really easy. It cuts right down the middle of Old Town. Here you'll have everything right at your doorstep. Convenience stores, food joints, bars and pubs, and of course, shopping. The sites you'll want to see are within reasonable walking distance and if you're not in the mood to walk, the tram system is easy to use.
It's important to note that the alcohol sold at the convenience stores in Old Town is cheap.
Besides walking, the trams are the best way to get around Bratislava. You can buy a 48 hour ticket that gets you access to the trams and buses at the orange machines by the bus/tram stops. It's basically the equivalent of five United States Dollars. I never once had my ticket checked while riding the trams or buses. It's an honor system that you respectfully buy the appropriate ticket and use it correctly.
The Buses are of great use when going somewhere that's outside the center city. For instance coming from the train/bus terminal to downtown and of course to Devins Castle. Just make sure you have your 48 hour public transport ticket stub and you can hop on and off whichever bus you want.
This is the big white castle that's on top of the hill. There is no possible way to miss it. Just follow the steep winding streets up the side of the hill (and likely the tourists) and you'll find it, I promise.
Inside the castle are a few different displays and museums. An entrance ticket gets you access to any and all of them. So, it's best to go earlier in the day rather than later. It's 10€ to enter to see the exhibits. One exhibit is about the reconstruction of the castle. Another is a maps exhibit that explains the history and geography of the local (Danube) region and finally, the best one, which is an exhibit about the Communist rule of Czechoslovakia. This specific exhibit talks about what life was like for the average citizen under the Communist rule. It also has a lot of displays and artifacts about the protests that ended up aiding in the fall of the Soviet Union.
Devin Castle outside center city of Bratislava
This is an ancient castle that has survived the test of time to the northwest of Bratislava. To get there you'll need to take a bit of a journey on a bus out of the city and then do a little bit of walking. On site you'll find tourist memorabilia shops and cafes and bars.
Before going in the castle I recommend taking a short stroll on the path around the castle and there is a memorial to 400 people that died fighting the Communist government. This memorial has real bullet holes from the fighting and a plaque in English about where it's from and what it means.
Inside the castle there are informational exhibits that describe the history of the castle and artifacts from the area. At the top of the castle you'll find great views of the surrounding plains and farmland.
Main Square - Bratislava
This is a beautiful small square in the center of Bratislava with cafes and restaurants. Here you'll find the Old Town Hall that has a tall tower. In that tower you'll find a cannonball lodged in the side of it. It's the original that has been there from when it got lodged in the side of the tower in 1809 during Napoleons bombardment of the city when it was part of the Austrian Empire.
Čumil Statute in downtown Bratislava
Bratislava is one of the most walking friendly cities I have ever explored. In all honesty, just walk through Old Town. Then go to Main Square. Then walk past the Old Town Hall in Main Square. Turn around and go back through the Old Town Hall and back through Main Square and find another main street and keep walking. Walk in circles in the city. At this point you'll probably stumble upon the world famous Čumil statue.
Bratislava is walkable and it's beautiful. By walking, I guarantee you'll stumble upon something fun like a heated game of giant street chess or a Slovakian folk music performance.