On June 28, 2009 Stephen Hawking threw a party for time-travelers. He announced the party the day after it happened, and according to Hawking, no one came.
NAZI Germany had a anti-tobacco movement, their research was silenced after the war.
Princeton University conducted a study which proved that, despite common misconception, squirrels remember where they buried their nuts.
Christopher Columbus correctly predicted an eclipse to trick the native inhabitants of Jamaica into giving him food and supplies.
Some people theorized that the problems that initially plagued the Hadron collider were the result of time travelers sabotaging the operation in order to prevent some unknown future problem.
Building a time machine is believed to be scientifically possible but requires building a gigantic particle accelerator in space, stabilizing space-time foam, plucking out a wormhole, enlarging it and connecting it a gravitational field.
If space is truly infinite and has an isotopic matter distribution, then probability dictates that there is an exact copy of you in the universe within 10 to the 10^28 meters of you, due to the finite possible arrangements of matter.
Students studying crows at the University of Washington wore wigs and masks because the crows would remember their faces and harass them for the remainder of their college career.
In 1956 the US government placed beer near a nuclear explosion to see whether it would still be drinkable after a nuclear fallout, it was.