Geeks! You are allowed to talk about your work on a date!
No, really. You're not allowed to be boring about your work on a date. But you're also not allowed to be boring about your family, your reading material, your friends, personal anecdotes, travel plans, etc.
Deciding in advance that you're not going to talk about work when you are mutually interested in work is silly, silly, silly. Far better to get to having a comfortable, interesting conversation about work that mutates into a comfortable, interesting conversation about other things than to try to force the conversation in ways it won't naturally go.
When I lived with three other women physics students the summer I was doing research in Ohio, we were hanging around in our pajamas eating popcorn and getting to know each other. We were hoping to be friends extending beyond our work. And we did not set ground rules for the conversation about not talking about work. As a result, the conversation flowed from "bad boyfriend" stories to "bad lab partner" stories to "I dated my lab partner and what a bad idea that was" stories without lots of artificial starts and stops, and in talking about those things we ended up talking about our families and our groups of friends back home and the things we liked other than physics, and it was good. And no, that was not a date, but I'm pretty skeptical of rules of dating that treat "people one might date" as a completely separate category from "people one might be friends with."