I was thinking I would drop my flag to half mast for 9/11. I was going to drop it at sundown tonight (flag is lit). But I'm not sure if it appropriate or not.
In the United States, Patriot Day occurs on September 11 of each year, designated in memory of the 2,993 killed in the September 11, 2001 attacks.
On this day, the President directs that the American flag be flown at half-staff at individual American homes, at the White House, and on all U.S. government buildings and establishments, home and abroad. The President also asks Americans to observe a moment of silence beginning at 8:46 A.M. (Eastern Daylight Time), the time the first plane struck the North Tower of the World Trade Center on September 11, 2001.
ETA: From the actual legisation:
The President is requested to issue each year a proclamation calling on:
all departments, agencies, and instrumentalities of
the United States and interested organizations and individuals
to display the flag of the United States at halfstaff on Patriot
Day in honor of the individuals who lost their lives as a result
of the terrorist attacks against the United States that occurred
on September 11, 2001.