Ever try looking up the touring schedule of a favorite band, or the game schedule of your favorite sports team, on the Web? What a hodge-podge of calendaring information. Some list dates and locations only, some include the time. Some are simple lists, others are arranged visually like a calendar. In some cases, you can click on the item to do other things or get a better description of things, but in almost no case can you click on the item and add it to your own calendar. This would be such a natural thing for them to do for their customers, and we'd all really appreciate it, too; but I guess there isn't enough profit in it.
Still, I am working on something like that in my spare time, which I hope to spread around to various bands and such. It will be XML-based probably, and will allow each item to have a link that downloads a calendar item into whatever calendar you use on your computer. I haven't worked out all of the details for what to do if you use a web-based calendar tool, but it should be similar. If it catches on, or at least if the concept catches on, someday soon we'll be able to add that concert by the Nine-or-Tenors to our calendar when we buy the tickets, and we'll be on our way to having our schedules improved in the way that e-mail and/or IM have improved our communications (without the spam I hope).