Startup Idea : What are people doing tonight in my city?

How many times you decide to go out with your friends but you have absolutely no idea what to do and where to go? So you might think What are people up to tonight?. The idea is a web platform where you can see how many people are doing what like: 120 users are going to the movie 200 users are going to a party 150 users are going to a concert... For each category there would be a dedicated page where you can discuss with other users what to do and where to go.