This Sunday, the 5th of Lent, the station is at St Peter's.
That means that the normal 5pm Solemn Vespers will be augmented by a Penitential Procession and Litany inside the Basilica. Members of the faithful can participate simply by turning up in the Basilica, whilst clergy and seminarians should report to the sacristy in the Choral Dress appropriate to their status.
The Vespers will then be followed by the blessing of the Veil of Veronica - a particularly solemn and moving ceremony. I could have sworn that Matt of the Holy Whapping had 'blogged about this last year, but can't find anything in the Shrine's archives.)