I second the travel talk as a conversation topic. Since Thanksgiving is a chance for many of us to gather, our experiences (travel, shows, books) make excellent conversation.
We also usually ask our 'old people' (my parents live in a retirement community so they bring 'a spare or a pair' who would otherwise be alone) to share memories of holidays when they were younger. It may seem corny to some of the more cynical readers, but sharing life stories builds tolerance and community and makes us linger at the table.