On Gaudete Sunday in Augsburg, Germany, the Bishop of that diocese, Walter Mixa, assisted "in choro" at Mass in the usus antiquior at the church of St. Margareth in Augsburg. The Mass was offered by a Fraternity of St. Peter priest, Fr. Walter Huber.
The bishop also preached and helped in the distribution of Holy Communion.
These sorts of participations on the part of acting bishops, and particularly ordinaries within their own dioceses, are quite important and can do a great deal to help support and foster Pope Benedict's new liturgical movement; a movement which is expressed in both within the context of the usus antiquior and usus recentior.
When diocesan ordinaries do these things, most particularly when done with evident respect, they first of all can help to build toward a more constructive, less polarized climate. Second, they can help to encourage priests who may wish to pursue the activity of re-enchanting their own parish liturgical life, whether that means applying the motu proprio within their parishes, or in their approach to the modern liturgy -- or, even better, both.
(reproduced from The New Liturgical Movement)