Show up at Bluff Creek, California on October 20, 1967 with a tranquliser gun and solve that Bigfoot mystery for good. 
I’d travel to 1969, and replace the guidance system on Apollo 11 with one that works. To think that they were actually this close with that old tech!
Of course, I’ll have to meet with the Moonkins and suggest they hide out for a bit, so that we don’t have an event similar to the “misunderstanding” of '82. Hopefully I won’t scare them off entirely…
Go back to ancient Egypt and stuff a Big Mac in a canopic jar that I know will be found in modern times. The My Little Pony figurines will go in the sarcophagus.
Add a chatspeak translation to the Rosetta Stone, in ASCII hex codes.
Show Leonardo da Vinci a circuit diagram for a binary adder and let him copy it into his notes.
I have a standing policy that if anyone asks me what year it is, I give them the wrong answer. I haven’t needed it yet, but it’s good to have a plan.
Have another friend walk into the bar about 5 minutes later wearing a trenchcoat and dark glasses, flash a mug-shot of you around ask if anyone has seen you (extra points if they can move a little oddly and talk with an Austrian accent).
Father children with women who were in power, preferably black/brown women, in black/brown societies. I’m white and the baby coming out a different color than any of the local men could produce would probably make some less developed cultures make the kid a god. Or they’d kill it. Idaknow…
Maybe I just want to boink some ancient hotties.
Ooh, my wife just reminded me of something:
One day, after a particularly unfortunate haircut, I decided I would like to do a version of this. I’d get dressed up, and run into a bar and proclaim, “I’ve come from the future, and I have an important message for you from the year 1979!!!”
Go back to the first Thanksgiving and make sure they end the meal with smoking huge amounts of weed.
It’s tradition!
Sneak into the printers and replace the text of Mein Kampf with Gandhi’s autobiography.
Replace the text on the Rosetta Stone with the lyrics to All Along the Watch Tower, and the phrase “all of this has happened before…”
[QUOTE=Ranger Jeff]
I’d leave an empty condom wrapper somewhere on Tranquility Base where Neil and Buzz couldn’t help but find it.
[/QUOTE]
My first thought was a sign that read “Cecil Adams was here” but then I decided more subtle would be better. Then I considered a used condom, but I thought that would be too yucky. So, that left me with either an unoccupied bra or the condom wrapper and I went with the wrapper.
Would the unoccupied bra have been a better choice?
Less funny than you’d think, unfortunately.
OK, this wins the thread.
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I can imagine wearing glowing clothing (which I apparently can purchase from Rhymer Enterprises Cross-Time Emporium) and traveling to the area around Palmyra in western New York state. The golden plates that I would bury there would instruct the faithful to drink heavily, dress immoderately and to enjoy the wonders of marijuana.
In this manner, when people are accosted decades later by bicycling youths, they will welcome their approach with a happy demeanor.
I’d go for a sunlounger, beach towel, and a pair of sunglasses, plus a trashy novel, and maybe a little note saying ‘Gone for lunch’. I’d leave the same at the South Pole.
I’d say you should make it a German beach towel, but that’s a joke they wouldn’t get for another 60 years.
At European beach resorts the German tourists have a reputation for getting up early, “reserving” the sunloungers by the pool by draping their towels over them and then going off to breakfast. This infuriates the British tourists no end, who consider this behavior impertinent as they don’t get up that early.
This is my favorite.
•Bribe D.W. Griffith to produce an (faithful) adaptation of “Roots” instead of “Birth of a Nation.”
•At the premiere, swap out the reels of “Return of the Jedi” with “Revenge of the Sith.”
•A few exciting games of “who can start a nuclear war with the least amount of effort?” I bet, with the right details, I could pull it off with a properly timed phone call.
•Frame Fredric Wertham as being a Soviet plant, tasked with sabotaging the fighting spirit of American youth by rabble rousing against mediums of fiction that hinder communist indoctrination. Evidence including an Order of Lenin, with citation personally signed by Beria.
I’d go far enough forward to get a few really good portable holographic projectors and just kind of Scooby Doo my way through history.
I’d sneak up behind Kennedy during the most tense moment in the Cuban missile crisis and pop a balloon.
I’d go back to 1851, find someone who could do at least a passable reproduction of “Washington Crossing the Delaware,” and commission him to do “Washington Crossing the Street” only closer to the style of the Leutze original than Gary Larson. Might as well get the parody into play right away, rather than have to wait 130 years for it, you know.
I’d dig up the lyrics to the most painfully sappy songs of the 1960s and 1970s that I absolutely couldn’t stand. Then I’d find some fourth-rate magazine from the 1960s that published reader-contributed sappy poetry, go back to 1960, and get those lyrics published under my name for purposes of establishing copyright. So when Bobby Goldsboro wrote “Honey” for instance, I’d point out that I had the copyright for his lyrics, and take that song off the air or pay up, buddy.