Actually nothing much happens on the Eve of Thaipusam. If you want to capture the real colours and the dramatic portraits, head on down the temple @ Serangoon road) around 11ish in the morning and hang around till 3ish in the noon. After that proceed to the temple @ Tank Road to capture even more dramatic portraits in the evening. My advice to you is to stick to the temple @ Serangoon Road, that's where most of the shutter bugs will find their cameras and lens useful! Cheers!