The 9th Ultimo Science Festival is on from September 3-12. It’s “10 days of serious science fun for adults, families, school groups, for young and old and in-between, for geeks, non-geeks, for everyone with curiosity”.
There are some really interesting events from curator tours at the Powerhouse thorough to the science of coffee, from stand-up science comedy to the Einstein lecture on astrophysics. There are also a number of activities specifically aimed at younger kids (although once again there appears to be a lack of engaging activities for teenagers).
In addition to all that you can see and do at the Festival, the organisers are calling for volunteers to help with the organisation.
For all the details see the website here.