Preparing for small talk sounds like a strange concept, but if you're not confident about spontaneously coming up with a conversation topic, it can help to have a few lines prepared to smooth out the odd encounter.
Aja Frost over at The Muse has compiled a large list of one-liners you can have in store for parties, work gatherings and other social occasions where you'll want to mingle and network. While some are a bit specific and even a little odd ("Would you rather work four 10-hour days or five eight-hour days?"), there are quite a few solid suggestions:
What’s the next trip you have planned? Are you reading any good books right now? I’d love some recommendations. How about shows? Where’s the last place you traveled? What did you do there? What surprised you the most about your current job?
Hit up the article for other suggestions — they're split into categories to help narrow downs your choices.