The so-called Manhattanhenge occurs twice a year when the setting sun aligns with the East-West streets of Manhattan's street grid.
Here you have the Manhattanhenge 2012 dates:
Half-sun on the grid:
May 29 @ 8:17pm
July 12 @ 8:25 pm (You might be on time if you are in NYC!)
Full-sun on the grid:
May 30 @ 8:16pm
July 11 @ 8:24 pm
Do you love sunsets? What do you prefer: sunsets or sunrises?