Hi,
It's every wednesday evening. Every first wednesday of the month it's at KC Dunaj and it starts at 17:30. The other wednesdays it moves around. So it's just a bunch of people who meet up in a bar to talk to each-other. There are different tables and every table carries a flag. When you're sitting at the table with the Flag of the United Kingdom you have to speak English, but there's also a German and a French table and many more.
The event has a facebookpage. You should find more information on there.
Greets