Hungary is located in central Europe. It's capital is Budapest. There are a lot of great reasons to visit including great food, beautiful architecture, music, culture, and of course awesome thermal baths. A lot of the climbing is found in old quarries. Lots of limestone.
The official language is Hungarian (Magyar) but many people (and almost all young people) speak English quite well. The official currency is the Forint. Euros are accepted in bigger stores and touristy places but it's probably best to have Forint with you for day to day needs.
There is a guidebook that covers pretty much all the climbing areas in the country. It is called "Magyarország Sziklamászó Kalauza" (Climbing Guide of Hungary) by Gozony Gergő. There are excellent pictures of the routes at all the crags covered and the guidebook is written in Hungarian and English. Highly recommended. Pick up the second edition at any of the Mountex outdoor sporting goods stores - www.mountex.hu/termek/80401-112-0
Mostly likely you will fly into Ferihegy International Airport in Budapest. Traveling by train or bus from other European countries is likely to lead you to Budapest as well.