The thing to keep in mind here is that if you're intent on just having a one-night stand, then you don't really need to worry much about having a lot to discuss. Rather, get just drunk enough to loosen up, and then talk about whatever comes to mind. In these types of situations what matters are looks and personality. What you actually talk about matters very little. If you're sincerely confident, at ease, engaging and funny, you're set. Don't put too much emphasis on the outcome, because you'll tie yourself up. Instead, just talk to any girl that you think is hot, and approach her and let things unfold. Don't plan what you're going to do, don't come up with topics to discuss ahead of time.
Tried and true topics:
Making fun of fat girls at the bar (she'll take it as a compiment that you find her attractive).
Asking obviously stupid questions (what's your favorite number?, how do you feel about mismatched socks?, are eggs dairy or meat?, etc). Ask her dumb questions in a pseuodo-serious tone, and if she's intellegent, she'll get the humor and play along.
Also, don't hesitate to touch her. Not creepily obviously. But eye contact and body contact are crucial.
Finally, don't be the guy that has it in the bag but then doesn't pull the trigger. The moment you get that inkling that she might want to kiss you, or go home, do it. If it doesn't work, big deal.