From my experiences in open houses, here are a few questions that should be asked when doing/visiting an open house. These questions usually spark up a conversation that allows for interaction on both sides.

(In no particular order)

Agents:

 1. Are you working with a Realtor? (This gives you the option to go after them as buyers, or respect the agency laws)

2. Are you looking for something particular in a home? (It would be wise to get to know the inventory so that you can pin point homes that match their criteria)

3. How long have you been looking for a home? (Lets you know where they are at in the stage of homebuying. Or lets you know if they are just tire kickers)

4. How did you hear about this open house? (Let's you know how well your marketing is)

5. Have you been pre-approved with a lender? (Also lets you know if they are serious or not)

6. How soon were you looking to move? (Determines motivation and time frame)

7. Do you own or rent? (Determines current housing committment so that you know if they have to sell, or can get out of their lease once they find the right home)

8. Have you seen anything on the market you like? (Determines criteria for their next home)

9. What would your dream home consist of? (Allows for the buyer to speak freely of what their next home is going to be like)

10. Are you looking in a particular area? (Are they in the right marketplace?)

Any and all of these questions should help you engage in a conversation that will allow you to communicate efficiently with a visitor at your open house.