I'm okay with small departmental groups - i think i have a warm and relaxed style BUT I now, in my new job, have to do 200+ people conferences (30 min type things on my topic). I have never done this and I'm a bit shit scared. I'm a planner though- i have 5 weeks and I want to immerse myself in watching good engaging speakers. I'm never going to be flamboyant or inspirational - I'm looking for interesting and engaging. Any Ted type talk steers to good speakers that i could realistically emulate would be much appreciated.