There are three things that are generally identified with St. Patrick's Day: The first is drinking, the second is hangovers and the third has slipped my mind, for some reason. Regardless, since 1737 Americans have been celebrating the Patron Saint of Ireland with songs, parades and responsible, legal alcohol consumption. And while St. Patrick's legacy may largely be based on exaggeration and glamorization, the industries that support the day are very real.

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Every year, millions of dollars are poured into St. Patrick's Day marketing, promotions, events and special offers. Though over 40 million people in the U.S. claim Irish descent, March 17 is a day when we're all a little green. (For more green readings, see 6 Leprechaun Leaders For St. Patrick's Day.)

The Wearing of the Green
It's believed that St. Patrick used the green three-leaf clover to explain the Holy Trinity to Irish Pagans in an effort to convert them to Christianity. Obviously, the plant has remained as a symbol of the March 17 festivities, but the color has branched out to even more St. Paddy's symbolism.

Retail chains dedicate entire sections of their apparel departments to selling green t-shirts, shamrock glasses and shot glasses with hilarious and irreverent slogans on them. Some chains, like Sears and Walmart, bank heavily on these items for last-minute and impulse purchases.

Online custom apparel printers like CafePress and Zazzle also fare well on official-unofficial holidays, customizing their home pages and product lines accordingly. During the recession, in 2009, people between the ages of 18-24 spent an average of $36.05 each on St. Patrick's Day clothing and accessories. This year, that same demographic is expected to spend $40.18.

Drinking from Patrick's Pot
Believe it or not, there's an actual reason we drink on St. Patrick's Day. As legend has it, Pota Phadraig (translated to Patrick's Pot) is celebrated to remember St. Patrick's persuasion of a stingy innkeeper to fill his patrons' glasses to overflowing. Naturally, whiskey was the drink of choice, and no whiskey company has seen more progression in the U.S. than Jameson.

In the mid-1990s, the U.S. government launched a campaign to promote Irish heritage on St. Patrick's Day. In 1995, Jameson's sales topped 10 million bottles. The following year, sales reached one million cases, and Jameson was named the fastest growing spirit brand, globally.

The Guinness beer company is another alcohol-maker that flourishes around St. Patrick's Day. More traditional than simply dumping green dye into stock draught, Fergal Murray, Guinness's head brewmaster, travels to pubs worldwide to train bartenders how to execute "the perfect pour." The drink is so widely praised that custom draught taps, bottles and cans were designed to spotlight the beer's unique taste, texture and appearance. (Consumer spending is one statistic that can be used to tell if we're coming out of a recession. Learn more in Holiday Spending: The Key To Economic Recovery?)

Eating the Irish Stew
There's nothing more exciting or appetizing than corned beef and boiled cabbage. Throw some soda bread into the mix, and you're eating like Douglas Hyde on Lá Fhéile Stiofáin in a post-Cogadh na Saoirse world. Irish cuisine is widely celebrated on St. Patrick's Day by eating establishments of all sizes. While Abrakedabra, the most popular Irish chain restaurant, is located exclusively in its home country, the best alternative stateside for some authentic Irish cuisine is undoubtedly your local pub.

The real winners when it comes to Irish food festivities are the makers of supplementary food and drink items. Green Jell-O, made by Kraft Foods, and suppliers of green dyes - some kinds used to color draught beer, and others to color the rivers that run through major American cities - see a significant surge in profits before the annual holiday. While there have been some concerns over the environmental and health effects of the dye, manufacturers assure us that they are biodegradable, organic and harmless.

Go A Little Green

As with most government-instituted holidays, awareness of the genesis of St. Patrick's Day is fading year by year. The celebrations, however, seem to be growing constantly. Even in the down economy, when most people have significantly cut their entertainment budgets, St. Patrick's Day remains one of the big money makers for local businesses and large corporations alike. Obviously, the alcohol industry (which includes bars, pubs, restaurants and liquor suppliers) fares the best at this time. And as the Irish always say - translated to me through a $6 t-shirt: "You can't drink all day, if you don't start in the morning." Erin go Bragh.

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