From the "websites you should already be using" category, comes Pollstar, a database of worldwide music concerts. Starting 25 years ago, as a professional music industry print guide, it has grown into the world's largest database of international concert tour information.
This is probably one of the best and under-rated Web 1.0 sites still around. Besides the obvious artist and city concert search, you can also search by venue, which is a nice touch. The tour information is usually up before it appears on Ticketmaster or the individual artist's web page. Email alerts to tour changes are a convenient and only semi-stalkery way of following your favourite band.
Over the years they have added more "premium" and ad-driven content, but the database is still free, and the site is still in my top 10 list of "most useful web-resources." What are the other 9? You will have to wait and see.