I danced with a girl dressed in 80s style clothing. Her friends were leaving, and we talked for a bit. Before she leaves, I throw in a comment I made up on the spot, but it sounded pretty good, and it got me her number.

Me: You guys have fun. Give me a hug, cuz I'll probably never see you again. [hug] Isn't that weird?
80sGirl: What?
Me: Well, we all meet so many people, have fun, and never see them again. Nobody realizes it, but there's a million different possible futures ahead of us.
80sGirl: Yeah, that's why we gotta make the right decisions.
Me: But, how do we know? Who knows, the girl I was dancing with before you could be the woman of my dreams. For all I know it could even be YOU.
80sGirl: Well--
Me: How scary is that, right? I mean, YOU!? Haha
80sGirl: Haha. Shut up! [hits my arm]
Me: [take out my phone] You know what? I'm gonna get your number, who knows what dark path this will lead me down.

BAM! It was totally random, and on the spot, but I will log that one away for future use. Try it out!