What do you program GUIs in?

Everything seems to be in C++. Is that what /prog/ uses too?

http://en.wikipedia.org/wiki/XML_User_Interface_Language

XUL (/ˈzuːl/ ZOOL), which stands for XML User Interface Language, is a user interface markup language that is developed by Mozilla. XUL is implemented as an XML dialect; it allows for graphical user interfaces to be written in a similar manner to Web pages.

XUL! XUL! XUL UBER ALLES