Insane Guest

Fantastic concept, but it's something that would have to blow up drastically to get the attention it would need to serve it's purpose. The specificity of it is why it would need so much attention. Take an example (Radiohead), a band which with an estimate would need at the least 20,000 "Craves" to get the venues attention, it would be hard to get (assuming) 20,000 people who all agree on a certain venue. I took a quick look at the website, which looks great by the way, but I couldn't figure out how the location plays out. Is it based off of the users sign-up location? (Certain mile radius of Zip Code, State, City?) There is also the obvious of the band or managers willingness to play at the venue, but the part where the website makes it easy, is guaranteeing that there is indeed a fan base where they are being asked to play. Adding a section for bands to sign up was a very smart move, as something like this could be ideal for lesser known or up and coming bands. To get more attention, you definitely need to spread this website all over the Internet. Music communities like last.fm, Reddit's Music subreddit etc. where it can potentially be free to get the word around.

Creating a Kickstarter, would be a good idea to raise awareness of the website, and raise money to buy adspace for places like Pandora, Allmusic, Spotify, music magazines, any place that has people who are already going out of there way to discuss, listen, discover, or purchase music.
If there is a market, it will sell, but it's a numbers game and for this case, it has to be of a massive amount, potentially chaotic. I think it's a genious idea, godspeed to you mate.