While your victim is away from his computer, change all of his browser bookmarks so they go to porn sites or site with obscene material. Be sure to keep the title the same though, this way he or she won't know its changed until they click on it.

Create a new 'fake' profile on MySpace claiming to be a new girl in school. Tell alot of boys personally where to meet her at lunchtime. Give each of them the same location and time. Then watch as dozens of boys go to the same location looking for a hot chick that doesn't exist.

Change your victim's screensaver so it is a scrolling marque and says something like "(victim's name) is gay and eats shit"

Change your victim's computer so they need a password to get out of 'screensaver' mode.

This prank is for that annoying co-worker who is always sending out pesonal emails, chatting online with friends and using company time to talk on cell phone to boy/girlfriend. All you have to do is go to their email when they are away and set it to "send blind carbon copies" to your boss's email address.

Stick a floppy disk in the floppy drive. The user will not be able to boot windows up until the floppy disk is removed.

If you have a co-worker who leaves his cubicle to get a drink or smoke, then chances are he or she is also leaving their email or word processing software open as well. If they do this and are in the middle of typing something, go up to their computer and type the word 'SHIT' in the middle of their document. They will end up emailing it or printing it like that if they don't double check it.

Sign up for an online dating service and use her name and photo if you have one. Then describe her as being desperate and horny. Be sure to leave her email address or phone number so any guy can contact her.

Sign your victim up for free porn email and put him on alot of unwanted newsletters and spam lists.

If you press CTRL+OPTION+APPLE+8 at the same exact time on any Mac OSX computer the screen will change to a black and white negative of what the current screen is. To undo this, just press the same keys again.

If you have a website with alot of traffic then you know how expensive bandwidth can be. There are alot of theives in cyberspace that will just use your images on their site while at the same time just linking to your image host. The perfect payback for this is to change the image names from time to time and replace the old image names with a different image. You can use an animated gif that reads 'I Am Gay' or some other creative image.

This is a great prank to play on someone who knows very little about computers. While he or she isn't paying attention change their scrolling screensaver to say this: Attention Windows Customer, I am sorry and need to inform you. Your system has been infected with a very serious virus and your entire system will explode in exactly 30 seconds, 29 seconds, 28 seconds...

Purchase your victim's .com domain name. Example: JamesCharleston.com then post embarrasing stuff about him on the website and send him the link.

When your victim is away from his computer, go into the setting and increase the speed of the mouse to the fastest. When he gets back, he will be unable to control the curser.

While your victim is away from his or her computer, change the double click setting on the mouse. To do this, just go to to start, settings, control panel and then mouse. Make it so fast that it is nearly impossible to do.