I single-handedly organised a half-day workshop for 80k, including doing the room bookings, the tech setup, the refreshments (couldn't buy them cheaply, I bought the crockery and food myself) and got feedback from the attendees of the sort "best catered event I've been to in 3 years of being in Oxford uni".

I've also completed my first term of university, and learned loads (of computer science, and also about my abilities in general).