September is here, and there's plenty to watch as the market goes back to school. Let's go over a few of the upcoming days to watch.

Sept. 10
This could be the day Apple (NASDAQ:AAPL) fans and shareholders have been waiting for. Reports of Sept. 10 as the iPhone 5S presser have been circulating for a couple of weeks. Recent reports that Apple blocked vacation requests for dates later in the month virtually confirm that the consumer-tech giant is bracing itself for heavy demand in the coming days.

What will we get? The loudest chatter is for the new iPhone to have the same form factor as the iPhone 5, with added features including the ability to use fingerprint detection to unlock the screen. That's pretty yawn-worthy stuff. The rest of the world will keep an eye on the potential of a cheaper iPhone, allowing Apple to market an entry-level device without having to sacrifice modern features. 

Apple stock has surrendered more than 30% of its value since peaking the day the iPhone 5 came out, so there's pressure on the tech bellwether to come up with something new.

Another event taking place earlier in the day will be unlikely to generate the same kind of media buzz, but there's something interesting about seeing Green Mountain Coffee Roasters (NASDAQ:GMCR) host its first ever Investors Day presentation.

Don't be surprised if we see more innovation out of Green Mountain than from Apple. The company behind the Keurig brewer has hinted at entering new markets, including carbonated beverages, energy drinks, and even soups. 

Sept. 12
The retailer that turned yoga apparel into a premium mall category will report a week from Thursday -- and there's a lot riding on lululemon athletica's (NASDAQ:LULU) fiscal second-quarter report. 

Has the company truly gotten away from the embarrassing recall earlier this year of its Luon yoga pants that were practically see-through? It seemed to be bouncing back in its most recent quarter, but now it will be time to see whether one of the fastest growing retailers still has legs.

There will be a lot to prove. Analysts see Lululemon's sales growth decelerating to 21% for the period, with earnings per share clocking in lower than a year earlier. 

Sept. 17
There's plenty of buzz surrounding the release of Grand Theft Auto V in two weeks. That's not surprising, since it's been more than five years since Take-Two Interactive's (NASDAQ:TTWO) Grand Theft Auto IV wowed the market, scoring initial sales records for the video-game industry.

That also happens to be around the same time the industry peaked in terms of the sale of hardware and disc-based software. New consoles are coming in November, and it will be interesting to see whether that plays a part in the initial demand for this particular release in mid-September.

The market's betting that Take-Two's game will turn things around. GameStop (NYSE:GME) told investors two weeks ago that it sees a double-digit spike in comparable-store sales this quarter, and Grand Theft Auto V will be the key contributor.  

GameStop is coming off nine consecutive quarters of year-over-year declines in comps, so Take-Two isn't the only one hoping this month's release will be a smash hit.

Longtime Fool contributor Rick Munarriz owns shares of Green Mountain Coffee Roasters. The Motley Fool recommends Apple, Green Mountain Coffee Roasters, lululemon athletica, and Take-Two Interactive and owns shares of Apple and GameStop. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.