Before I became a mom, I didn't know how to talk to people about their children. I had no idea at what ages you crawl, walk, ride a bike, lie about your age to get on Facebook, etc.
So, I started asking my parent-friends, sincerely but obliquely, "So, what is [Kiddo] into these days?"
I found that open-ended question to work like magic. Parents lurve talking about their kids. Any expression of interest is usually enough to kick off a good conversation.
Now that I am a mom, I've realized that's actually a pretty good question. I like when people ask me that. I try not to ramble on like someone whose brain has been eaten by their toddler. I try to keep it short, sweet, and to the point.
If you asked me that today, I would say: Trucks and dinosaurs.
What would you say?