Factual error: Bluto crushes a beer can against his forehead. Steel cans are too strong to crush like that. Aluminium cans weren't introduced until approximately 1965, although the movie was set in 1962. http://www.cancentral.com/brochure/historyTimeline_f.htm. (00:07:55 - 01:20:20)
Plot hole: How on earth can Bluto and his mate not know that the exam paper they are completing is different to the one they stole and studied for? They'd have to study for it - what's the point of stealing it otherwise? It is not a multiple choice exam - they are seen writing answers out in full. How can they not notice that the questions (and therefore the answers) are different to the ones they memorised? Why do they have to be told later that someone 'stole the wrong exam paper'? In order to make such a mistake they would have to be illiterate, not just stupid -.and as the closing sequence makes clear the Delta House fraternity members aren't even stupid - they are just lazy.