Timeout is a company that keeps you up to date with whats going on in some of the biggest cities all over the world. For Japan there are two versions and you can reach both of them by going to timeout.jp. There you can choose to either view the Tokyo version or the Kyoto version.
Via Timeout Tokyo/Kyoto you can find whats going on in the cities, from gigs to cinemas listings to events going on and what pubs to visits or museums to go to. Timeout is definitely a good site to check whats on.
A big plus – the page is English too, so maybe give it a try on your next trip to Japan.
Check out the site at http://www.timeout.jp