Flag Do's and Don'ts (from the U.S. code):
Do fly the flag from sunup to sundown. Leave it out overnight only in a well-lit area.
Don't display Old Glory with its blue field of stars facing down -- it's a signal of extreme distress.
Do keep the flag from touching anything below it.
Don't raise it in rain, sheet, snow, etc.
Do destroy a seen-better-days banner in a dignified manner, preferably by burning it.