Hey You Fools, It's April 1

April 1, 2009— -- Many people woke up this morning to a very different world.

Google announced today that it had finally conquered artificial intelligence, Travel Web site Expedia is now offering flights to Mars for $99 and after 188 years, London's Guardian newspaper has ditched its print edition and has switched to an all-Twitter version.

"Experts say any story can be told in 140 characters," the paper said.

The story detailing the change is much longer.

YouTube is also testing a brave new layout. Click on your video of choice and get ready to blink your eyes in disbelief. A number of YouTube videos are playing upside down. The site says it's part of an ongoing effort to "improve the way you watch videos online" and even suggests that you flip your monitor upside down, tilt your head to the side or, better yet, move to Australia.

But before you update your Facebook page to tell your friends about that upcoming trip to the red planet, you might want to check a calendar. This isn't just any old Wednesday. It's Wednesday April 1, more commonly known as April Fools' Day.

The interplanetary travel and the move to tweet journalism were just a couple examples of the practical jokes playing out on the traditional day of worldwide hoaxes.

In the holiday spirit, ABCNews.com invited our readers to submit their favorite April Fools' Day stories. Some are funny, some are bizarre and some are just downright mean. Don't worry, though. We won't pass judgment on you; we're just sharing some of our favorite tales. And here are some of our favorite responses:

We start with Janice from White Hall, Ark. A few years back, Janice thought it would be funny to send a little gift to her boyfriend at the time. Imagine the look on the guy's face when the small blue bear and the balloons reading "Congratulations on the New Son" arrived at his office.

"His co-workers thought it was so funny. He did not think so," Janice tells us.

This next tale should be a warning to all: Think twice today before you accept food from friends or co-workers. Brian from Phoenixville, Pa., decided one year to buy some Oreo cookies and remove the filling.

"That's the best part," he said.

He refilled the cookies with white baking soda toothpaste. Then on a hot day, when it looked like the icing might have melted, he shared his altered cookies. Probably not the best afternoon snack, but at least all of his friends had sparkling white teeth.

If you thought that was mean, consider the story from Mark, of Roanoke, Va.

One April 1, he woke up very early, stood on a chair in his house and lit a match under the smoke detector.

"When it went off, I yelled 'fire,' and my wife and three kids got up and ran out of the house in their pajamas," he wrote in an e-mail.

When they got to the front yard, Mark yelled out the window "April Fools' Day."

"I am still alive but have been locked up in my basement for the past 23 years! It was fun though," he wrote.

April Fools' Baby Jokes

Last year, Sherry Inskeep of Westerville, Ohio, was just a few days short of having a baby. She was sitting in the living room watching TV with her two teenage children.

"I had filled a snack-size Ziploc full of water and put it in my pants pocket. While I was sitting in the living room I used a pin to puncture the Ziploc so it appeared my water broke," she wrote. "My kids had no idea what to do! I went into the bathroom to leave them hanging a minute before I came out cracking up laughing, and then said, 'April Fools'!'"

P.M. McConnel, of Brownsville, Ore., is married to a man who we hope had a good sense of humor, or at least teeth of steel. His birthday happens to fall on April 1. One year, McConnel decided to make him an angel food cake -- out of concrete.

"He thought it was real and tried to cut it," she wrote.

Ouch.

April 1 can also improve some people's level of intelligence. Or at least that's what Marilyn Daly, of Southold, N.Y., hopes. Her plan: Watch "Jeopardy" alone in the late afternoon.

"Then when my husband and I watch in the evenin, I will know most of the answers," she wrote.

Then there are those who like to play jokes on the jokesters.

Joyce Venniro, of Rochester, N.Y, tells the story about being invited to dinner by her prankster brother and his family. She decided to bring some homemade dinner rolls.

"In a selected few I put a ball of cotton into the dough before I baked them. I put egg wash and sesame seeds on them, just as I did on the rest of the rolls," Venniro wrote. "Then I made sure the 'special rolls' were carefully put so that he would take the cotton filled ones. His face was priceless!!!"

Office Pranks on April 1

Sometimes the boss gets to have a little fun.

Robert Rainey, of Los Alamitos, Calif., suggested leaving your secretary a note with a phone number saying that it's urgent she return the call from a "Mr. Lyon." She dials the number and the operator says: "Los Angeles Zoo, can I help you?"

"I've had some people go on and ask for the 'Mr. Lion' … even after knowing they're talking to the local zoo," Rainey wrote.

Karen Hargette, of Newport News, Va., and a friend also decided to have a little fun in the workplace.

They took the tank off the office water cooler, dropped in a couple of live goldfish, sealed the top of the tank with plastic wrap and put it back on the cooler.

"Whenever our co-workers went to get water, they saw the gold fish and went nuts," she wrote.

Even true love isn't immune from a little joking.

Andrew from Detroit decided to propose last April 1 to his girlfriend. The big moment arrives, he gives her a ring box, she opens it and inside is a note saying "April Fools'."

"I let that play out for a couple of minutes, then I pulled out another ring box (with a ring in it) and she said yes," Andrew recalls.

Sometimes that loving humor doesn't go away, even after years of marriage.

Brenda Williams, of Pittsburg, N.H., says she once wrapped an elastic band around the spray nozzle at the kitchen sink and asked her husband to get her a drink.

"When he turned on the water the sprayer got him right in the stomach. Oh how funny!!" she writes.

And finally, we get this story from Beth DeLauder, of Stafford, Va.

"My most (and least) favorite April Fools' gag," she wrote, "was my mom giving birth to me on this day 45 years ago."