Thanks Elizabeth
A Moodle Choice would work but the problem of making sure that you get the people who commit to attending may be difficult to solve.
I have, when faced with this issue in the past, used the Choice as a negotiating mechanism. If you set the poll with a range of time choices such that people can view the results and change their vote then you can reach a consensus/compromise that way.
You can't please everyone of course, it's always 3 AM somewhere in the World!
The notes and videos are a good fallback for me so I don't want to overstate the issue.
Cheers
Richard