You will be surprised how well people respond when you are just trying to start a conversation. Most people are usually pretty nice and will respond in a positive way. You are just trying to meet this person. So it can be about anything. To get the conversation started, see if you can find a sincere compliment to give them.
People love getting a compliments.
If for some reason they do not respond, then you still may have made someone's day by giving him or her compliment. The key to giving someone a compliment is being sincere. People will appreciate it more if it is an honest compliment. If you cannot find a compliment to give, then think about where you are. This festival sure has good food.