I spent nearly all of it with my 3 year old son, Andrew. The very best bit was him singing "Happy Birthday" and blowing out the candles on my cake. It was the bit about "Happy Birthday, Dear Daddy" as he pointed at me that did it.
Another highlight : Andrew treating me to a ride on the virtual roller-coaster at Questacon. I suspect this was originally part of a superannuated multimillion-dollar Qantas flight simulator. You don't get the full gee forces, but it's good enough to fool your sense of balance. And of course, being "virtual", it can do manouvers that would be far too dangerous to ever implement in reality. Rather like certain scenes in "Indiana Jones and the Temple of Doom". Here's an accurate description :
The simulator is a big red box that moves around on hydraulics while the 10 people inside look at a frighteningly real computer simulation on a screen where the front window ought to be.Great Fun.
You hurtle along a rail, down tunnels, uuuuuuuuuup and dooooooooooooown, then leave the rails and go floating through the air towards certain death.
Unless you keep telling yourself not to worry because you are really in a big red box moving from side to side and up and down on hydraulics, it can be pretty harrowing.
There's another Questacon virtual roller-coaster implemented as a Flash game on the Web. Design your own, then ride on it. At Questacon, you physically move equivalent modules around, before pressing the button that sends the small low-friction metal car careering around your design at an impressive speed. They've yet to mount a TV camera on the car, but I suspect they will, one day.
Highly recommended for any visitor to Canberra.