This Hindu temple is primarily for the worship of Shiva's wife, Kali, who destroys ignorance, maintains world order, and blesses those who strive for knowledge of God. The box on the walkway to the front entrance is for smashing coconuts, a symbolic smashing of the ego, asking the gods to show "the humble way." The coconuts have two small "eyes" at one end so they can "see" the personal obstacles to humility they are being asked to smash.
Inside the temple in the main hall are three altars, the center one for Kali (depicted with 16 arms and wearing a necklace of human skulls) and two altars on either side for her two sons -- Ganesh, the elephant god, and Murugan, the four-headed child god. To the right is an altar with nine statues representing the nine planets. Circle the altar and pray to your planet for help with a specific trouble.
Around the left side of the main hall, the first tier of the gopuram tells the story of how Ganesh got his elephant head. A small dais in the rear-left corner of the temple compound is an altar to Sri Periyachi, a very mean-looking woman with a heart of gold. She punishes women who say and do things to make others feel bad. She also punishes men -- under her feet is an exploiter of ladies.
Here's a bit of trivia: Red ash, as opposed to white, is applied to the forehead after prayers are offered in a temple devoted to a female god.