One of the best things to have happened in my life is to come into contact with the lectures of Swami Paramarthananda Saraswathi, a disciple of Swami Dayananda Saraswathi. Swami Paramarthanandaji has been giving talks on Vedanta in Chennai and other places for a few decades. His recent lectures can be found at http://www.vedantavidyarthisangha.org/. His old lectures can be bought at http://www.sastraprakasika.org/. People have posted several of his lecture series on the internet.
There are several teachers of the tradition of Swami Dayananda Saraswati who are teaching in various places in India. http://www.arshavidya.org/teachers_india.html gives a good list of them.
Swami Paramarthanandaji has given numerous lectures on the Bhagavad Gita in different levels of detail. He delivered a series of 250 lectures covering Bhagavad Gita verse by verse. A devotee, P.S. Ramachandran of Coimbatore, has transcribed the entire lecture series and has made it available to the public as a PDF file. You can access this invaluable resource here: http://arshaavinash.in/?wpdmdl=790  If that link does not work, you can access a copy here.
The chapter summaries of the series have been transcribed separately by some students of Vivekananda Study Circle, IISc, Bangalore. You can find that here.
Earlier I had published my lecture notes on this website. Now, with the availability of the full transcript, my lecture notes are redundant. I have removed them.
Salutations to the holy feet of the Guru, the Lord and His devotees.