After reaching an all-time high, Apple's (NASDAQ:AAPL) shares have fallen off a cliff over the past few weeks. Since mid-September, the stock is down 24% to a valuation that has a lot of investors scratching their heads. Apple trades at 12.2 times trailing earnings, has nearly a quarter of its $511 billion market cap in cash, and is expected to have another blowout quarter after the holidays.

What Apple needs is a move that will kick-start investor enthusiasm about the stock again. So, I've come up with three potential ideas, which I've listed below from most likely to most improbable.

The $100 dividend
No company -- not even Apple -- needs to have a $121 billion cash hoard. If we spread it out to the 940.7 million shares outstanding we get a total of $128.90 in cash per share held by Apple. So, why doesn't Apple pay a one-time special dividend of $100 per share? If Apple did this, it would still hold $27.2 billion in cash, more than enough to run its business.

There's recent precedent that this may be a good move. Wynn Resorts (NASDAQ: WYNN) recently announced a special dividend of $7.50 per share and the stock jumped 7.2% -- or more than $8 -- the next day.

Investors are waiting for Apple to return more money to shareholders and a big dividend would instill confidence that Apple's cash generation machine will be returned to shareholders.

An app-expanding spending spree
Apple has been known for killing some of the most successful third-party apps by developing internal apps. Google's (NASDAQ:GOOGL) Maps app was most famously dumped for an internally developed map app, but there are others Apple has nullified. Pocket's capabilities are now built into Safari; a multitude of free texting apps have gone by the wayside with iMessage now integrated into the iPhone; the iCloud negates the need for a service like Dropbox; and Reminders and Notes do the work that other apps once did.

So, Apple is clearly keen on adding capabilities to its own apps with little regard for developers. But why not buy some of the key apps Apple uses and build on the capabilities others have already developed?

Yelp (NYSE:YELP) is integrated with Maps and could be had for $1.5 billion or so. This would be great to incorporate even more intimately with Maps and would give Apple a foot in social media.

Netflix (NASDAQ:NFLX) isn't built into iOS, but it is built into the Apple TV and it would augment some of Apple's own capabilities in iTunes. For $6 billion, the company could probably be bought. Competitor Hulu has been rumored to be worth $2 billion and is also another option.

Another interesting acquisition target could be Square. The company is squarely (pun intended) in the center of the payment revolution that Apple would no doubt like to be a part of. Apple already has over 400 million iTunes accounts with credit cards attached, the largest set of accounts in the world. Square, iTunes, and the addition of near-field communication on the next iPhone could be a game changer for payment solutions, adding a highly coveted business to Apple's fiefdom. Square recently raised funds that valued the company at $3.25 billion, so $5 billion or $6 billion in cash could get the job done.

If Apple acquired all three companies, we're talking a spending spree of about $13 billion or so, a drop in the bucket for Apple.

Big, bold acquisition
It hasn't been Apple's style, but with $121 billion in cash, the company could also make a huge acquisition. So, what about buying chip maker Intel (NASDAQ:INTC)? I know, it sounds outlandish, but hear me out.

Apple's share of the PC market is now about 12% and growing, so demand from Apple is certainly a meaningful chunk of Intel's business. It's also been rumored that Apple could soon have the capabilities to use an ARM-based chip in its iMacs. Why leave and develop a new chip when you can buy Intel outright and integrate its technology to develop your own chip?

Intel has also gained little traction in smartphones and tablets, which Apple dominates. Buying Intel would bring the engineering capabilities of both companies under one roof, able to optimize chips for Macs, iPads, and iPhones.

The dollar figure also isn't as outlandish as it may initially seem for Apple to bring production in-house. Reports are that Samsung spent $9 billion to build a plant in Austin, Texas that primarily produces Apple chips. Intel has its own fabs and could become a dedicated supply source.

To put icing on the cake, it would be great to see Microsoft (NASDAQ: MSFT) and computer makers like Dell (NASDAQ: DELL) and Hewlett-Packard (NYSE: HPQ) scramble to find a new supply of chips so they don't have to buy from Apple.

An acquisition of Intel may not pass regulatory muster and no doubt has other hurdles, but I don't think it's as crazy for Apple as it initially seems and would certainly create a splash.

Foolish bottom line
Apple needs to do something to excite investors. Maybe it has something in the works, like Apple TV. But I think these three moves would be good for Apple and shareholders.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.