Apple has yet again launched a contest to celebrate app download milestones within its App Store. Today the company has announced the 50 billionth app download winner will receive a US $10,000 App Store gift card, plus $500 cards to the next 50 additional app downloaders.

Within iTunes, there is a live counter showing apps being downloaded–currently just under 800 million downloads are remaining to reach 50 billion. Apple does say this counter is for “illustrative purposes only” though.

Apple says the promotion is open to entrants 13 years or older and excludes the province of Quebec. Canadian winners will be required to answer a skill testing question. You can also enter up to 25 times per day without purchasing or downloading an app here (Update: Apple’s link wasn’t working; new link added–thanks James).

Apple held a similar promotion last year to celebrate its 25 billionth app download, which resulted in a winner from China winning the $10,000 iTunes card after downloading Where’s My Water in late April. Good luck!