#ColbertCountdown: A Look Back at the Best 'Colbert Report' Moments, First Up: 'Truthiness'

We're officially on notice: The Colbert Report's Stephen Colbert will end his show on Dec. 18.

The 50-year-old replaces David Letterman when The Late Show host retires in 2015, and will leave behind his satirical news program — and his pompous character. As Colbert might say: "I'm really going to miss me." And we will, too.

So what better way to celebrate the comedian’s achievements — and mourn his departure — than with #ColbertCountdown: A look back at some of our favorite moments from the past 10 seasons?

We'll add one new post for each of the remaining 28 episodes to air until his last show. Starting... now.

Related: How 'The Daily Show' Became Comedy's Best Incubator

There are plenty to choose from. The Colbert Report, which launched as a spinoff from The Daily Show with Jon Stewart in 2005, originally parodied Fox News hosts and featured the character "Stephen Colbert," a loud-mouth hothead hilariously fueled by indignation and rage.

It grew from there, as Colbert attempted to interview every representative in Congress (Better Know a District), tried to give Republican presidential candidate and pizza mogul Herman Cain the "Colbert Bump," and even hosted his show from Iraq to support the troops. He's started a Super PAC, crooned with John Legend, and high-kicked with the Rockettes.

Related: Stephen Colbert to Host the 'Late Show': 9 Things to Expect

An unforgettable moment came in the pilot episode when he coined the term "truthiness." "I will speak to you in plain, simple English," the fake-pundit promised, as he introduced his made-up word. "Now I'm sure the word police, the wordinistas over at Webster will say, 'Hey, that's not a word.'" But, as the host joked, "The truthiness is, anyone can read the news to you. I promise to feel the news at you."

Colbert had the last laugh when Merriam-Webster named "truthiness" the 2006 Word of the Year.