In a meeting workspace get all agenda items from a list programmatically.

using Microsoft.SharePoint.Meetings;

Sample code:

using(SPSite site = new SPSite(<enter your workspace url>))
using (SPWeb web = site.OpenWeb())
{
    SPMeeting meeting = SPMeeting.GetMeetingInformation(web);

    SPQuery query = new SPQuery();
    query.MeetingInstanceId = (int)SPMeeting.SpecialInstance.AllButSeries;
    query.Query = @"<Query>
                       <Where>
                          <IsNotNull>
                             <FieldRef Name='ID' />
                          </IsNotNull>
                       </Where>
                    </Query>";

    SPList list = web.Lists[<enter your list>];
    foreach (SPListItem item in list.GetItems(query))
    {
        Console.WriteLine(item[item.Fields.GetFieldByInternalName("Title").Id]);
    }
}