I'd start by introducing myself. I'd then ramble on about how I did not have a speech prepared. Something funny would pop into my head, so I'd say that. People would laugh. I'd listen closely for the most unique laugh, point at them and do my best impression of the sound they make with the hopes of making that person laugh hysterically. Laughter is contagious, people would start laughing at the sound of laughter alone. Everyone will go crazy, my five minutes will be up, I will say thank you and drop the mic.