I was concerned about getting (free) tickets to see the Arizona Memorial at Pearl Harbor. So, I went online, and found this:

http://www.nps.gov/valr/planyourvisit/feesandreservations.htm

Since my guests are from China, I decided it's worth paying $4.5 for reserving three tickets online.

Note: Bags are not allowed, but there is a storage booth (for fees).