What happens on April 15 each year in MLB?

In what year was the first MLB All-Star Game played? In what year was the first modern World Series played? Which team won the first modern World Series in 1903? In which city was the first All-Star Game played, at Comiskey Park? What is the home run celebration feature at Citi Field that rises from center field? Which team's mascot is the Phillie Phanatic? Which team's mascot is Mr. Met? Which team holds a "Racing Presidents" race during home games?