Source: Frankieleon, Flickr.

Here we are, in the thick of tax season. That means many mailboxes and bank accounts are receiving tax refunds. A tax refund can feel like a windfall, even though it's really a portion of your earnings from the past year that the IRS has held for you, in case you owed it in taxes. Still, it's a small or large wad of money that you suddenly have in your possession. Here are some ideas for how you might best spend it.

First, though, a tip: If you're eager to spend your refund, but haven't yet received it, you can click over to the IRS's "Where's My Refund?" site to track its progress through the IRS system. Now on to the suggestions for things to do with your tax refund:

Pay down debt: Paying down debt is a top-notch idea for how to spend your tax refund -- even more so if you're carrying high-interest rate debt, such as credit card debt. If you owe $10,000 and are being charged 25% annually, that can cost $2,500 in interest alone each year. Pay down that debt, and it's like earning 25% on every dollar with which you reduce your balance. Happily, according to a recent survey by the National Retail Federation, 39% of taxpayers plan to spend their refund paying off debt.

Be sure to have an emergency fund. Source: StockMonkeys.com.

Establish or bulk up an emergency fund: If you don't have an emergency fund, or if it's not yet able to cover your living expenses for three to nine months, put your tax refund into such a fund. You'll thank yourself if you unexpectedly experience a job loss or health setback, or even a broken transmission.

Open or fund an IRA: You can make your retirement more comfy by plumping up your tax-advantaged retirement accounts, such as traditional or Roth IRAs. Better yet, you can still make contributions for the 2014 tax year -- up until April 15. The maximum for 2014 and 2015 is $5,500 for most folks, and $6,500 for those 50 or older.

Add money to a Health Savings Account: Folks with high-deductible health insurance plans can make tax-deductible contributions to HSAs and pay for qualifying medical expenses with tax-free money. Individuals can sock away up to $3,350 in 2015, while the limit is $6,650 for families, plus an extra $1,000 for those 55 or older. Another option is a Flexible Spending Account (FSA), which has a lower maximum contribution of $2,550. There are a bunch of rules for both, so read up before signing up.

Visit a financial professional: You can give yourself a big gift by spending your tax refund on some professional financial services. For example, you might consult an estate-planning expert to get your will drawn up, along with powers of attorney, a living will, and an advance medical directive. If a trust makes sense for you, setting one up can eat up a chunk of a tax refund, too. A financial planner can be another great investment. Even if one costs you $1,000-$2,000, they might save or make you far more than that as they optimize your investment allocations and ensure you're on track for a solid retirement.

One way or another, you'll need to sock money away for retirement. Source: Steven Depolo, Flickr.

Make an extra mortgage payment or two: By paying off a little more of your mortgage principle, you'll end up paying less interest in the long run. Do so regularly, and you can lop years off of your mortgage, too.

Save it: You might simply park that money in the bank or a brokerage account, aiming to accumulate a big sum for a major purchase, such as a house, new car, college tuition, or even starting a business. Sums you'll need within a few or as many as 10 years should not be in stocks, though -- favor CDs or money market accounts for short-term savings.

Invest it: Long-term money in a brokerage account can serve you well, growing and helping secure your retirement. If you simply stick with an inexpensive, broad-market index fund such as the SPDR S&P 500 ETF, Vanguard Total Stock Market ETF, or Vanguard Total World Stock ETF, you might average as much as 10% annually over many years. A $3,000 tax refund that grows at 10% for 20 years will grow to more than $20,000 -- a rather useful sum.

Give it away: If you're lucky enough to be in good shape financially, consider giving some or all of your tax refund away. You can collect a nice tax deduction for doing so, too. Even if you're not yet in the best financial shape, it's good to remember that millions of people are in poverty and in desperate need of help.

Invest in yourself: You might also invest in yourself, perhaps by advancing your career potential via some coursework or a new certification. You might even learn enough to change careers entirely, to one you like more, or that might pay you more. You can also invest in yourself health-wise, perhaps by joining a gym, signing up for yoga classes, or hiring a personal trainer. If you've been putting off necessary dental work, a tax refund can come in handy for that, too.

Traveling is another great way to spend your tax refund.

Create wonderful memories: Studies have shown that experiences make us happier than possessions, so if your financial life is in order, and you can truly afford to spend your tax refund on pleasure, buy a great experience -- such as travel. You don't have to spend a fortune, either. A visit to Washington, D.C., for example, will get you to a host of enormous, free museums focused on art, history, science, and more. For more money, perhaps finally visit Paris, go on an African safari, or take a cruise through the fjords of Norway. If travel isn't of interest, maybe take some dance or archery lessons, or enjoy a weekend of wine-tasting at a nearby location.

Don't end up, months from now, wondering where your tax refund money has gone. Make a plan, and make the most of those funds, as they can do a lot for you. Remember, too, that you may be able to split your refund across several of the options above.