On the eve of the Advent Season, the Holy Father will celebrate a vigil of prayer for all nascent human life. This vigil coincides with the celebration of the first Vespers of the First Sunday of Advent, that marks the beginning of the Advent season. The celebration of Vespers and the vigil will be integrated together.
The Holy Father has invited the Bishops of the world, and all Catholic communities and movements, to join him in this vigil in their particular churches throughout the world. The United States Conference of Catholic Bishops has prepared a form of service for this vigil that can be downloaded from here. If you are not able to take part in a vigil in your parish or diocese, these resources would allow you to pray the vigil at home or in a small group.
Searching the diocesan website, I have not been able to find any events marking the vigil in my own deanery or diocese, though there might be events taking place that have not been posted to the aether. I was away last weekend, so have missed my usual parish newsletters for the week. Brentwood Cathedral appears to have a "previous booking" for a concert, and many parishes have Saturday evening Masses, which offers some explanation.
There will be a celebration of the vigil at Westminster Cathedral at 7pm, with Archbishop Vincent Nichols.