Just a heads up.
Checking back thru the Jetstar posts I found the old dates of their 3c 4c 5c sales for their birthday which usually is announced the first or 2nd week of May.
I'm expecting a 6000 seats for 6 cents (or $6) sale over 6 minutes (or hours) plus take a friend for free sale which always comes out about a week after the domestic birthday sale.
The only question this year is whether this will be released only to those who have taken up a Jetstar Mastercard or to Jetmail Members. From a publicity perspective they will probably go with the Jetmail option which usually means the website falls over after 30 seconds.
Last Years - Jetstar's 5th birthday celebrations - Cheap Flights