A list of things which have happened since the development or in less time than the development of Duke Nukem Forever.
The first press release I can find concerning DNF is dated April 25, 1997.
Grand Theft Auto 1, 2, London, III, Vice City, likely San Andreas
Fallout, Fallout 2, All eight (to my knowledge) Infinity Engine games and expansions, and three Baldur's Gate console spinoffs
Final Fantasies VII, VIII, IX, X, X-2 XI, Tactics, Tactics Advance, Crystal Chronicles, Origins, Anthology, Chronicles and the Ergheiz & two Mysterious Dungeon spinoffs
Legend of Zelda: Four Swords, Wind Waker, Ocarina of Time, Majora's Mask, Link's Awakening DX, Link to the Past GBA, Legend of Zelda GBA, Oracle of Seasons, Oracle of Ages
Unreal, Return to Napoleon or wherever the hell that was, Unreal Tournament, UT2k3, UT2k4 and at least 4 games off the top of my head that use its engine
Quakes 2 and 3, and God knows how many games used those two engines
Thief 1, 2, 3
The Sims and all seven expansions
Tony Hawk's Pro Skater 1, 2, 2x, 3, 4, Underground
Madden NFL '98, FIFA '98, NBA '98 and NHL '98 for the Super Nintendo, and NHL '98 for both the SNES and Genesis
Might & Magic VI, VII, VIII and IX
With the exception of Meridian 59, every MMORPG apart from MUDs (I may be off here; at any rate UO was released five months after DNF was announced)
Romance of the Three Kingdoms VI, VII, VIII, IX, Dynasty Warriors 1-4 (and 2 expansions), Dynasty Warriors: Empires, Samurai Warriors, Kessen 1 & 2, Dynasty Tactics 1 & 2, Mystic Heroes
Every Dance Dance Revolution game
Every single Pokémon game released in the US
Every Deer Hunter game
Chessmaster 5500, 6000, 7000, 8000, 9000, 10th Edition, with additional non-PC ports
Twenty (to my knowledge) Mega Man titles, for GBC, GBA, GC and N64, not including direct ports
Thirty (to my knowledge) Star Wars titles, again not including direct ports
And something new! Working Designs is famous for taking absolutely forever to release a product. Since the announcement of Duke Nukem Forever, WD has released Albert Oddesy, Magic Knight Rayearth, Sega Ages (maybe), Raystorm, Elemental Gearbolt, Lunar: Silver Star Story, Sillhouette Mirage, Lunar 2: Eternal Blue, Alundra, Arc the Lad Collection, Raycrisis, ThunderForce V, Vanguard Bandits, Silpheed and Gungriffon Blaze, with Growlanser Generations out shortly. Working Designs CEO Victor Ireland has made approximately 3,710 Usenet posts since the announcement of Duke Nukem Forever.
Other Facts:
The Voyager 1 spacecraft has travelled approximately 2.5 billion miles since the announcement of Duke Nukem Forever.
The rovers Spirit and Opportunity were proposed, authorized, announced, designed, launched and successfully landed upon Mars within the timeframe of Duke Nukem Forever's development.
The majority of the children who were entering high school the school year following Duke Nukem Forever's announcemnt are now eligible to drink.
Going back to the Duke Nukem theme, not only had the real Manhattan Project been successfully completed in less time than it has taken Duke Nukem Forever to be completed, but the entirety of World War II, from Hitler's invasion of Poland on September 1, 1939 to the signing of the surrender papers on the USS Missouri on September 2, 1945, took place in less time than this game. World War I was even shorter.
One out of every seven people on Earth was not yet born when Duke Nukem Forever was announced. Approximately one out of every seventeeen has since died.