The Australian National Maritime Museum has a fantastic area called the
"Kids Deck".  This is an area where families can come in and do a range of
activities that are usually designed to fit in with the current major
exhibition.  In a seperate area, it is really a "kids area" and is very
popular.  The web address is www.anmm.gov.au.  The Kids Deck isn't
mentioned directly, but there are email addresses you could try for more
information.