Set aside the images of fireworks lighting up the sky that you typically associate with the month of July. When it comes to investing, summer is usually more like the laid-back barbecues and lazy slices of apple pie that you may also associate with Independence Day.

Don't sleep through July!

There will be plenty of events taking place this month, and a lot of them should move the market. Sure, earnings season kicks in toward the month's end, but there are also plenty of other dates on the calendar that pose challenges, threats, and -- investors can hope -- opportunities.

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

July 11
If you're hoping for a cheap -- and legal -- copy of Microsoft's (NASDAQ:MSFT) upcoming operating system, this is your last day to pre-order a copy of Windows 7 Home Premium as an upgrade for Vista and XP users for just $49. Microsoft's promising platform will hit the market with a suggested retail price of $119 in the fall.

A lot is riding on Windows 7. Vista has been the butt of operating-system jokes, especially in Apple's (NASDAQ:AAPL) effective "I'm a Mac" ads. Fans of Vista will argue that the knocks have been unfair, but all sides can agree that Windows 7 is Microsoft's best chance to matter in a future that threatens to make operating systems less important in a future more focused on cloud computing.

It's a good sign for Microsoft that the pre-orders -- at least so far -- have been selling briskly.

July 15
Harry Potter and the Half-Blood Prince becomes Time Warner's (NYSE:TWX) latest installment in the blockbuster series to hit a multiplex near you. It's also the first theatrical release since author J.K. Rowling completed the seven-book series. Will that heighten or diminish interest in the movie series as Time Warner milks the last two books into three cinematic experiences?

Box-office receipts are trending ahead of where they were a year ago, so momentum is on Time Warner's side. However, there's also a busy slate of rival flicks hitting exhibitors this summer. Can Harry Potter's spell over audiences continue?

July 17
Fridays are typically sleepy days on the news front. Few companies want to test shareholders' mettle by delivering quarterly reports heading into the weekend. However, three meaty stocks with plenty to prove -- Bank of America (NYSE:BAC), Citigroup (NYSE:C), and General Electric (NYSE:GE) -- will all be stepping up to the podium on July 17.

All three stocks started out the year as Dow components, until Citigroup was booted last month. They have a few other things in common:

July 29
The last thing that Sirius XM Radio (NASDAQ:SIRI) subscribers expect is a rate increase. The merger between Sirius and XM was based on an agreement that rates would be frozen for a couple of years.

However, that didn't stop Sirius XM from bumping up its rates on discounted secondary receivers in the same family in March. It also began charging for online streaming, which in Sirius XM's defense was accompanied by an upgrade in the quality of its Web-based offering.

Sirius XM is allowed to make these adjustments. It's also entitled to pass along on any music royalty fee increases -- and it will do just that when monthly rates go up by $1.98 on July 29.

That increase is going to become a huge test for the satellite-radio operator. Subscriber growth peaked during last year's fourth quarter, when Sirius XM watched over more than 19 million receivers. It closed out the March quarter with just 18.6 million subscribers.

Will the July increase shake out even more subscribers, or will it be a cash flow dream as fans pony up for long-term commitments to lock in the current rates?

Things can cut either way, so join me in making sure you're wide awake this month.

Some other reads to get you through the month:

Apple is a Motley Fool Stock Advisor recommendation. Microsoft is a Motley Fool Inside Value pick. Try any of our Foolish newsletter services free for 30 days.

Longtime Fool contributor Rick Munarriz owns a Miranda July CD, but he doesn't own the month of July. He also doesn't own shares in any of the stocks in this story, but he is part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.