Collect of St John Before the Latin Gate (See Note)

According to the Apostolic Penitentiary, a partial indulgence is granted to those who on the feast of any Saint recite in his honour the oration of the Missal or any other approved by legitimate Authority.

V. O Lord, hear my prayer.

R. And let my cry come unto thee.
Let us pray.

O God, Which seest that sins and sufferings do on every side rise up to trouble us, grant, we beseech thee, that we may find a shield in time of need through the glorious intercession of thy blessed Apostle and Evangelist John.
Through Jesus Christ, thy Son our Lord, Who liveth and reigneth with thee, in the unity of the Holy Ghost, ever one God, world without end. 

R. Amen.

I would assume that this indulgence also attaches to the recitation of the Troparion and Kontakion of the Saint of the day in the Eastern Calendar which are in my Eastern Rite post at 00.06.

Nota bene - The Feast of St John Before the Latin Gate was removed from the Universal Calendar in the Johannine Reforms of 1960, so I don't know if the indulgence still applies.