Firstly, I would simply bathe in the relaxness of 2 parentless weeks, turn on music really loud, stuff like that.
Second, I'd spend a great deal of time gathering information about migration to Australia. I don't want my parents to know about my plans, they'll know about them everything is set and I'm pretty much ready to go (which would still take about a year or so from now). I'd write letters, make lots of calls, travel to the embassy for information, anything. No parents in the house would be a delightful opportunity.
Last but not least, I'd take the opportunity to learn to iron, use the washing machine, the dish washer, anything, so I'm better prepared on living on my own.
So no, I wouldn't throw crazy parties or anything like that. I sound dull now, don't I?