This is a message I've just received (all times are US ET):
Today all US Financial markets will be observing four separate moments of silence in remembrance of the 9/11 attacks. The following minutes will be observed, 8:46, 9:03, 9:59, and 10:29 EST. In addition to these minutes, the NYBOT and NYMEX will close for an additional 21 minutes on the last moment of silence for the 21 members of the NYBOT & NYMEX that perished on 9/11. While it is encouraged that all trading cease during these times, GLOBEX trading may continue outside of the exchange.