Done the theme parks!
Watched the requisite school holiday movies!
For something more cerebral the kids will also enjoy this winter break I suggest you drop by Brisbane's Gallery of Modern Art (GoMA).
The highlight of GoMA's 2010 winter program is an exibition of works by Australian-born, London-based sculptor Ron Mueck.
A bit of a warning though, the exhibit features some graphic materials some audience might find offensive.
One of my kids described the displays as "creepy" but enjoyed the visit nonetheless.
You be the judge. Don't miss the event if ever his works are in your area.