From Mistake 10: "People interested in local events (that one is a perennial tarpit)". Would you please give an example or elaborate a little bit more on that?
I fear I may heading for the tarpit...
This is one of those ideas that people think of, notice that no one is already doing it, and decide that there is therefore an opportunity. But the reason no one is already doing it is not that no one has thought of it. It's one of the most common startup ideas. The reason no one is doing it is (I believe) that users don't want it.