A little busy with work these days, so I have only pictures to offer. The first is of the gopuram (tower) of the temple in the town of Tiruvannamalai, in Tamil Nadu. Notice how the style and color of the gopuram differs from that of the Brihadishwara temple of Thanjavur. Behind the temple is the sacred Arunachala hill which has drawn many saints over the years, the most recent of them, Ramana Maharishi. During the Tamil month of Kartigai (Oct-Nov), a light is lit atop the hill and it is visible for miles around.
The second picture is an informal shrine for kaval deivam -- guardian spirits. I came across it in the countryside between Krishnagiri and Tiruvanamalai. If my understanding is right, these gods are specific to villages in Tamil Nadu -- that is, they are not pan-Indian like say Shiva or Vishnu. More information here and here.