We took my 6 year old (and 2 year old...although the 2 year old could care less about it). We had just finished an exciting unit study on Ancient Egypt in our homeschooling studies, my son was ENTHRALLED with all things ancient Egypt. One book we'd read was "Tut's Mummy Lost...and Found" which is a Step 4 book. We also had Usborne's "Time Traveller" book (section on Ancient Egypt), read about Anceint Egypt in "Child's History of the World," looked up information on teh internet, check out books from the library, ended up studying some basic archaeology stuff ("Achaeologists Dig for Clues" is a good children's book talking about how that field works).
Then, when we got to the science museum (where Tut's Treasures was being shown), we watched the IMAX movie, "Mysteries of Egypt" before going into the treasures room.
JM was entranced by the IMAX movie, he didn't care for the jewelry, sculptures, or other "boring" things. He enjoyed seeing the beds, chairs, games, and finally was really impressed by the mummy.
One that was disappointing to Dh and I that while it was billed as "Tut's Treasures" they were actually replicas of the ones in the museum in Cairo (I believe it is in Cairo). They were very detailed replicas, but it took some of the "mystique" out of is for us. DS didn't know any different, and we didn't tell him.
Today, DS can tell you the names of the Pharaoh's who built certain pyramids, he knows about life in Ancient Egypt (like where the people lived, how they travelled to other cities, who did what jobs, different classes during that time, etc.). I say TAKE them, but prepare them for what they will see by reading up on Ancient Egypt some.