I highly recommend The Sacred Page. It is a terrific website maintained by Catholic Biblical scholars Brant Pitre, John Bergsma, Michael Barber and John Kincaid.
Every week they post commentary on the Mass Readings.
In addition to this Brant Pitre records videos explaining the Mass Readings. They last about 20-30 minutes and are crammed full of fascinating information.
They are available through Catholic Productions. You have to pay for this content, but it’s good stuff. Learn more about it here at their home page.
It is a great way to prepare for Mass and it is a wonderful resource for preachers, teachers and catechists.