The market's been rallying ever since its springtime leap. The "sell in May and go away" cynics have missed out on a deluge of opportunities.

Can the good times last through the end of summer?

Now that the "easy money" has been made, the market still has a lot to prove. There will be plenty of market-shaping events taking place in September, and the last thing you want to do is assume that this vibrant rally is a lock to continue if the news doesn't live up to the hype.

Here are a few of the days I plan to approach with eyes wide open this month.

Sept. 9
Poor Activision Blizzard (NASDAQ:ATVI). The country's leading video game company is hitting the market today, Sept. 1, with Guitar Hero 5, but everyone's attention is on the Lads From Liverpool.

Viacom's (NYSE:VIA) Rock Band -- Guitar Hero's rival plastic-guitar franchise -- scored a major coup when it landed the Beatles for a band-specific release that hits the market a week from tomorrow.

There's a lot of buzz behind The Beatles: Rock Band, which hits the streets just as EMI is rereleasing a sonically spruced-up version of the band's catalog. Diehard shredders will point out that the fretwork on the Fab Four's legendary rock songs doesn't appear to be all that challenging. However, it's hard to deny the allure of this ambitious release of the most successful rock band in history -- not to mention a band that has shied away from digital distribution. Besides, the game will also add some challenging elements, including tricky three-part vocal harmonies.

You can settle for the $60 software, or you can plunk down $250 for the limited-edition premium bundle that includes Paul McCartney's bass controller and Ringo Starr's drum kit. George Harrison and John Lennon guitar controllers will be sold as accessories for $100 apiece. 

Viacom isn't the only one hoping to make a big splash here: Electronic Arts (NASDAQ:ERTS) is the game's distributor. Given the industry's moribund ways, a lot is riding on this title. If the industry still has a pulse, the market is about to find out. But if big-ticket music titles are out of fashion, developers will all be singing the Beatles' "Yesterday."

Sept. 15
We may never know why Microsoft (NASDAQ:MSFT) never took the hint. After a pair of uninspiring generations of portable media players, Zune HD hits the market on the 15th.

It's hard to bash the Zune, because it did offer up some new wrinkles. Social sharing, built-in FM transmitters, and the innovative Zune Pass music-subscription service are foreign to Apple's (NASDAQ:AAPL) iPod realm.

Yet the Zune has never managed to snag market share from Apple. Even flash-memory giant SanDisk (NASDAQ:SNDK) stands between Microsoft and Apple and renders the world's undisputed software champ into little more than a distant bronze medalist. Instead of bowing out quietly, though, Microsoft keeps raising the stakes. The Zune HD offers access to HD radio, a slick OLED touchscreen, and the ability to plug into a television to watch high-def video clips.

The new Zune is bold, but it might also be the Zune's last hurrah if it fails to nab relevant chunks of market share this time out.

Sept. 29
Casual dining has taken a back seat to fast-food chains during the recession, and rightfully so. When discretionary income is tight, going out to dinner is an easy luxury to forgo.

However, the burger chains are showing signs of cracking, a possible signal that there's a revival in store for the table-service eateries. We'll have a better indicator on dining trends when Darden Restaurants (NYSE:DRI) reports on the 29th.

Darden may not be a household name, but its concepts -- Red Lobster, Olive Garden, and LongHorn Steakhouse -- dot the country's high-traffic intersections. If hungry diners are ready to trade up from "dollar menu" deals to casual dining, Darden will be one of the first to know.

Some other reads to get you through the month:

Apple, Activision Blizzard, and Electronic Arts are Motley Fool Stock Advisor selections. Microsoft is a Motley Fool Inside Value recommendation. Try any of our Foolish newsletter services free for 30 days.

Longtime Fool contributor Rick Munarriz wonders why September rhymes with "remember." He owns no shares in any of the stocks in this story and is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.