A prolonged session of banter. That is having amusing, sometimes nonsensical, chat with friends or just generally having fun. The word is derived by combining banter with marathon (since a marathon is a 26 mile long race and thus
takes a long time to complete).
1.'What work did you do in class today?'
'We didn't do any work at all. We just sat around chatting. It was a total bantathon!'
2.'Are you going over to Paul's tonight?'
'Yeh of course, it'll be a bantathon.'