There will be a brief lecture before one of the pieces. Once this past winter they did this before an Agon; the orchestra rose up and the conductor and another person spoke about the music for about 10-15 minutes, with interspersed excerpts.
(They said about 4 times, "Don't worry, we'll get to the dancing soon." If they know that's what everyone's really waiting for, I don't know why they even bother. In my opinion, these lectures should be given optionally, during intermission or before the performance, only for those who are truly interested.)