Happy first Day of Summer.
This year's summer solstice fell on Friday, June 21, at 1:04 a.m. See National Geographic: Summer Solstice 2013: Why It's the First Day of Summer
The solstices are the results of Earth's north-south axis being tilted 23.4 degrees relative to the ecliptic, the plane of our solar system. This tilt causes different amounts of sunlight to reach different regions of the planet during Earth's year-long orbit around the sun.
Today the North Pole is tipped more toward the sun than on any other day of 2012. (The opposite holds true for the Southern Hemisphere, where today is the winter solstice, the shortest day of the year.)
As a result of Earth's tilt, the path of the sun across the sky rises in the lead-up to the summer solstice, then begins descending for the rest of the summer.
The first day of summer would spark celebrations in some cultures.
The banging you heard last night was not a celebration of the Summer Solstice, but the pots and pans were banging in celebration of the Heat's Championship hours earlier.