Firstly, you're not a weirdo, screw them... Their your grades. Let them get up and talk about cars and beer and whatever else 'supposedly'' makes a guy cool.
Why not talk on how planes land? IMO people are always interested in how some thing 71m long, 65m wide and 180,985kg's (B744) manages to touch down exactly in the centre of a piece of concrete 10000m long . Touch on ILS, Auto Pilot, Course Headings, COM/NAV settings and explain how they work together to get your classmates to Ibiza or wherever they think is cool. Make it idiot proof so they understand whether they want to or not.
Or you could talk on the prep work of Pilots, FO's and FA
's prior to take off (completing flight plans, way points and emergency landing airports.
A good fact very few know (bar the FA
's) is that cabin crew can, on trans-Atlantic/pacific flights, can walk up to 12 miles.
Aer Lingus, Proud to be Irish.