Twinkies are a myth. Ding Dongs or Snoballs…nothing else has the shelf life.
But I like the way you think. ;j
If we feed Twinkies to the Bog sacrifices, they’ll bob to the surface from the internal gasses.
Have the Lascaux cave painters add "E=mc2 to one of their paintings.
Arrange Stonehenge so it reads “42” when seen from the air.
or place a black rectangular stone(9’ x4’x1’) at the landing site.
I’d make sure that a few ivory-billed woodpeckers survived.
I’d change one thing: a word.
I’d go back to the last week in August, 1999. My freshmen year of high school. My first day. The day I first laid eyes on the most beautiful girl I’ve ever seen.
I’d approach myself, while I sat there alone in class, having arrived early, and tell myself “Hey, there’s no reason to be afraid of this girl. She’s not going to think you’re a dweeb. I know what you want to do is just sit there and pine and spend the entire year wasting any opportunity you have of meeting this girl, only to have her move away next year and be gone from your life forever, but get this: where I’m from, I actually had a second chance to meet this girl and I took it. We’re friends now. There’s no reason to wait 6 years. Just say ‘hi’.”
Then I’d come back to the present day to see if it had any varying effect.
Foil the assault on Nancy Kerrigan and release videotape evidence that Tonya Harding had a hand in it, thus keeping her out of the Olympics…not long after which Kerrigan realizes she had no excuses and zippo sympathy points, plus that Madonna/whore crap has been shot dead. 
Rescue Elian Gonzales at sea and return him to Cuba. Make sure his father knows.
In the 1972 men’s basketball gold medal game, cut the power to the stadium the instant time runs out.
On the first episode of Rush Limbaugh’s radio program, gather up a bunch of friends to call him repeatedly and tell him that he’s right about everything and anyone with half a brain knows it, but what he really needs to do is run for public office to make sure his vision of America comes to pass. Then do it for every successive episode. If he’s still doing his radio program after six months, get really hostile and berate him for wasting time preaching to the choir when his country obviously needs him so much.
Plant a Dead Sea Scroll bearing the message, “There isn’t a sheckel’s worth of difference between Arabs and Jews. The Holy Land belongs to everybody. Terrorism for any reason is pure evil and will get you sent to Hell. There is nothing good about innocent deaths, especially children’s. Enforcing a strict interpretation of Islamic law is nuts and has no place in any society.”
During the '92 media blitz on violence in video games, replace all the Mortal Kombat footage with Columns, then call in and loudly decry Sega’s portrayal of the wanton destruction of expensive jewelry.
Edit one episode of South Park so Eric Cartman gets killed at the end. Painfully. Messily. Destroy the original.
After Bob Knight’s third national championship, convince him to leave the small-time college game behind and move to the NBA. For which I’ll leave the fallout to your imagination.
I’d remove Hitler from his home at birth and have him adopted by a different family in a different country and see how things turned out- his life as well as the history of the world
I would play rock & roll for Beethoven and Mozart and some of those dudes and see how it influenced them.
I’d give smallpox vaccine and guns to the native Americans
Depending on how many alternate universes or do-overs I had, I’d go through each American presidential election and see what would have happened if the other guy had won.
I’d give the cavemen veggie burgers
I’d take a whole bunch of people to help me and I’d make food plentiful for our earliest ancestors and make sure it stayed plentiful to see if we might evolve differently.
I’d do other things with our early ancestors to see if modern-day humans turned out any different than they are now
this is a really interesting thread I’d better stop before I end up with two pages of ideas
Wait until this thread has pretty well died down and fallen off the front page for good, then go back to February 9 and post everyone else’s best posts in my name.
There’s no need to shoot the Messenger.
Widely introduce horses to the Bantu progenitors in the interior Tropical West Africa roughly 1000BC among the farmers, storytellers and warrior-classes. Education, travel, agriculture, warfare and commerce revolutionize the continent.
There are a couple of artistic changes I’d like to make:
[ul]
[li]Convince Kurt Cobain that time-travel is more fun than suicide. “Feeling Stupid and Contagious” at CBGB’s 1977 ensues.[/li][li]Bring back a nuclear generator and a huge AM radio transmitter to 1880s Kansas. Distribute crystal sets liberally to the soddies from Independence on west. Blast Chuck Berry, The Clash, Elvis Presley, and any other loud rock I can think of.[/li][li]Give Mozart a solar-powered CD player and CDs by John Coltrane, The Who, Opeth, Miles Davis, Rush, and Pink Floyd. Oh, and a pair of mirrorshades.[/li][li]Build a theater in 1900s New York City and show Predator, Terminators one and two, Jurassic Park, and every other big-budget effects movie I can think of.[/li][/ul]
Some others:
[ul]
[li]Show one group of primitive African tribesmen, back before humanity had left Africa, how to make really advanced recurve bows and teach them modern small-group squad combat tactics.[/li][li]Give the ancient inhabitants of the Fertile Crescent modern, improved strains of New World crops like potatoes, corn, peanuts, and tomatoes. Teach them how to rotate crops and preserve the land’s fertility using the crops I’ve given them.[/li][li]Make a website in 1994 and post news stories on it from a week in the future. Attach each story to a message board, Slashdot- and Fark-style.[/li][li]Teach Thomas Jefferson how to make an Edison phonograph. Get him to record for posterity the voices of every one of the Founding Fathers, and make sure those recordings are preserved.[/li][li]Teach Galen the germ theory of disease and give him a good enough microscope to prove it to him. Get him to write down solid antiseptic procedure in the medical manuals that would be used, largely unaltered, throughout the Dark Ages.[/li][li]Go back to the Library of Alexandria with guns and soldiers and lots of them. “THIS IS WHAT HAPPENS WHEN YOU FUCK A CULTURE UP THE ASS!”[/li][li]Give Leonardo da Vinci a whole library of modern physics and mechanics and technology with lots of schematic drawings.[/li][li]Start a company in the early 1980s and sell the bestselling microcomputer software (for Apple, IBM, Amiga, etc.) a year or two before it is actually developed and released. (With suitable logo and name changes, of course.) Use the money to go hog wild.[/li][/ul]
Oh, and buy the pimpest ride imaginable (tricked-out Cadillac low-rider, purple with gold trim, blasting bass and jumping hydraulics, hip-hop and rap soundtrack, etc. etc. etc.) and tool around every large European and American city in the Victorian era.
“Shiny, shiny pimpmobile…”
Go back to Pre-Colombian North & South America, around 200BCE, & give the most advanced cultures horses & cattle.
I’d turn Hitler onto pot–he wouldn’t have the time or ambition to take over countries and kill people if he was busy getting stoned and comtemplating the grooviness of the light switch.
Or I’d bring Led Zeppelin back to the '30’s and then when Hitler came out to make a speech at a Nazi rally people would throw stuff at him and yell “We want Led Zeppelin!” Yeah, that would put the skids on his career…
I’d switch Lenin and Abbie Hoffman so that Hoffman would be running around in St Petersburg yelling “The revolution will not be televised,” much to the confusion of the Russians, who in pre-TV days wouldn’t have any idea what he meant. And that would leave Lenin to be involved in the protests at the '68 convention…OK, that could get interesting.
Go back in time and invest in that fruit company that Forrest recommended.
I would leave a complete set of blueprints for the Honda Accord car with henry ford, in 1905. I’d also leave a working model steam engine with heron of Alexandria (ca 100 AD). I’d leave a calculus textbook with leonardo Da Vinci, and a map of the world with Columbus.
Go back and rearrange comic books so that Aquaman is a major player.
Slip obscene references and predictions of the future into the Zimmerman telegram.
Grab the 500 from Thermopolis, give them modern body armor, and let them go in a major city.
Convince the Chinese to look outward instead of inward when the age of Exploration was beginning.
Become Hefner’s business partner at the start, thus giving me a lifetime pass to drop by the Mansion anytime I want.
Oh yeah, I swear this has been a life long fantasy of mine, I’d arrange things so that Bob Dylan played a concert during the battle of Gettysburg.