Right.. and I assume there are those things locally everywhere -- but it's not online so people who plan on taking a vacation and touring some city can't make it line up with some concert they'd like to see -- at least not in the online world.
A lot of trips nowadays are booked by going to Priceline, Expedia, etc, to find Hotels, Airlines, rental cars, etc, but there isn't really a resource to find good classical performances by anyone at that time online.
For example, I know I want to go on vacation in January or February (whenever I can get plane tickets cheapest). The only other thing I know is that I would like to travel overseas, but really my main goal is to see a good piano concert, with or without symphony, hopefully including a work or two of Rachmaninoff

However, as I'm starting to look around, I can't plan this trip. Why? I have no idea where I want to go other than I want to see some rachmaninoff performed.
Now, I imagine being able to get onto this service that I'm thinking about and typing "Rachmaninoff" and selecting some dates. Then *walah* I have a listing of every rachmaninoff performance worldwide (well, *participating* performance, since if we don't know about it we can't list it), and I can start looking at cities and see what sounds interesting to me.
I just wanted to know if anyone here thinks there's demand, and if anyone else is interested in helping getting it launched after I make the site and stuff (if I decide there's demand for it).