I was unaware of it before but just looking on line it appears to have been running for acouple of years in Australia so I imagine it'll be back again next year. If you have a look at the web site
http://www.supanova.com.au/ Melbourne is just the start in oz, this year it's also on in the Gold Coast, Sydney, Perth, Brisbane and Adelaide.
Do I think it was worth the hassle? Yes, I'd do I again, my son loved it! Only things I'd do differently is get there a lot earlier and run to the token stand as soon as I got in the door. This would of saved a lot of waiting around I reckon.
I'm not sure what sort of numbers they get to these things but if someone said close to 100,000 I'd believe them. It was huge.