Yes, modafinil. The majority of the people I know use it. (So do I, but that's because I work an overnight shift... maybe once I finish this side project I'll be able to land a nice 9-5 software job.)
Modafinil, sold under the brand name Provigil among others, is a medication to treat sleepiness due to narcolepsy, shift work sleep disorder, or obstructive sleep apnea (OSA).[3][7] In OSA continuous positive airway pressure is the preferred treatment.[3] While it has seen off-label use as a purported cognitive enhancer, the research on its effectiveness for this use is not conclusive.[8][9] It is taken by mouth.[3]
You can buy it online, legally in the US anyways, probably in Aussieland too.