"What is going on here?"
Translation:Mi folyik itt?
Ah, not quite. Mi can mean both "we" and "what". Mit, however, is the accusative form of "what", when you need it as an object, like in "Mit csinálsz?" - "What are you doing?"
In "Mi folyik itt?" 'something' is doing the going-on, so that 'something' is the subject and mi needs to be in nominative case.