In a discussion with a few non-Indians who have houses here (one American and two Brits) they equate some of the festivals to psychological torture with highly amplified music (Indian music is an acquired taste for most non-Indians and that is at a normal volume) that goes on day and night for up to ten days continuously. And lest this be thought of as foreign hyperbole I can confirm that there are articles where local people complain of noise pollution from temples in the paper at least once a week.
Besides pongala I've only been to a single festival during my time here - this at a small temple near the tea shop where I get my breakfast. Frankly I found it rather dull after a while as it consisted of a single priest stepping (I wouldn't really call it dancing) around and around the elaborate construction shown in the photo below. Apparently at the end of his circambulation he turned in to Kali and that was probably worth seeing but it was hot and I ran out of interest.
Below this paragraph are photos of strings of lights, speakers, fluorescent tubes and amplifiers stacked up at the main Kovalam Beach bus stop waiting to be taken - probably on somebody's head - to whichever temple festival they've been hired for.
