New York City
Riga: What is the easiest way to get from Riga to Tallinn?
An easy way is to go by coach like Simpleexpress,Ecolines or Eurolines.It's cheap and direct!
Warsaw: 24-hrs in Warsaw
Depends on what you like,but I think the Warsaw Old Town is an ok option,from where you can cross the river and go to Praga (an artistic and at the same time pathological neighborhood:P ) and then come back to the Old town and walk...
New York City: What to see and do + restaurant ideas in NYC
For children I would recommend FAO Schwarzthe biggest toy store in the city,it's right next to Central Park so you can visit it on the way there!