This will be a talk by Bjarne Stroustrup, the creator of C++, about the evolution of the language, the current state, and the direction C++ is heading.
Some food will be served at the venue. And there is a bar where you can buy something to drink. The venue is just a few minutes walk from the train station.
PS: Bjarne is in Kongsberg because of the annual NDC TechTown conference (http://ndctechtown.com) where he is doing the opening keynote. There is a promocode available for members of Oslo C++ Users group if you plan to attend, please contact Olve.