If your forum starts its meetings with a conversation starter / ice breaker, have each member submit one at the retreat. This will insure that you have a supply of good questions throughout the year.
In some forums, it is always the moderator who has to think of the question. Moderators already have enough to do. The members need to take this off the moderator’s plate.
In many forums, a different member (usually the Day Chair) supplies the conversation starter at each meeting. Sometimes, this person doesn’t think about the conversation starter until the last minute – which is more likely to result in a perfunctory question. By asking for everyone to submit questions at the retreat, you increase the chances that your forum members will think more deeply and supply great conversation starters.