Just because Double Fine doesn't have enough of your money already, Amazon is offering a pretty swell deal -- selling Psychonauts, Stacking and Costume Quest for $9.99 on PC.
Psychonauts, obviously, is a bit of a classic, so if you haven't had the chance to play it yet, now's as good a Double Fine time to give it a bash. As for the two others, well I enjoyed both, particularly Stacking -- which has an awesome little central mechanic. I didn't enjoy Costume Quest so much, mainly because I'm not the biggest fan of turn based RPGs. That said, it has some really sharp writing and an adorable art style.
So, in conclusion... this sounds like a Triple Fine deal from Double Fine.
My name is Mark Serrels, and that was possibly the worst sentence I have ever written.
EDIT: Looks as though the deal isn't available to us in Australia -- but thankfully, as Beavwa kindly pointed out, the deal is available on Steam.