I attended Vasantahabba on a visit to Bangalore in 2001 and have been aching to go back ever since. It was definitely one of the best experiences I've had, ever. To find out how to make sure there is a Vasantahabba 2007, check this post.
I'm in Bombay for the weekend on some personal work and have been seeing huge billboards all over the place advertising the Kala Ghoda Arts Festival. From coverage at the official blog it seems to be an event that no art lover in Bombay should miss. Now I don't consider myself to be one of those artsy/intellectual types, but I'm still not happy that I'm probably not going to be able to take advantage of my trip to Bombay to see some of the events, like for example "Prayog" - An experiment in Bharatnatyam at Rampart Row.
But if you can, do check out the schedule and take advantage of this once-a-year amalgam of art. There's an HTML-only version of the schedule here if you have any trouble with the PDF link.
Update: Do check out the contests hosted at Caferati as part of the fest. The deadline for the Flash Fiction contest is gone (unless there's another extension) but the SMS Poetry contest is still on. So get your entries in quick!