Disclaimer: I assume anyone reading these pratical jokes is of sound mind and body...and knows the consequences of their actions
Dump a whole bottle of detergent into the toilet tank. This produces great billowing suds out of the bowl on first flush. Especially great if first flusher is sitting at the time.
Place a coin on the ground and wait for someone to bend down to pick it up. As they do, tear a piece of fabric and the'll think they just burst their pants.
Ask somebody what time it is when he/she is holding a glass of fluid (water, beer, etc) in the hand attached to the wrist where he/she wears a watch. You'll be surprised how many people pour fluid onto themselves trying to be helpful to you.
Tie a thin, almost invisable piece of thread to a coin and place it on the ground. Wait for someone to bend down towards it and pull it away at the last second.
Wait 'till someone is drinking a can of fizzy soda and when their not looking drop in some sugar or a sugar sweet. The soda will fizz up and start pouring uncontrolably out of the can.
When you visit your friends house, put some washing machine detergent in their dishwasher. Next time they run it suds will come oozing out the door.
Glue a dime on the ground and wait for people to come by and try to pick it up.
Get your friends email address and sign him up for various email newsletters from provactive sites (gay porn, communism, etc)
If you work at a department store slip some of those anti- shoplifting strips into the lining of your friends favorite jacket
Hand lotion inside of an air hose on the final assembly line is effective, but very vindictive. Use with caution
Saran wrap on reading glasses that have been left on desk is good. Trimming at edge of lens is hard but effect is great. Not usually noticed when first picked up but optical quality of saran is spectacularly bad.
Take a garbage can, fill it with water, and amateurishly balanced it on the door, ready to fall on him when he opens the door. (Now Knock on their door and run!)
Switch the "MEN" and "WOMEN" signs on a pair of public bathrooms while they're occupied. Great at airports, hotels, and bars
"This is the telephone company calling. There is some trouble with your line. Please do not answer any calls for the next five minutes or the person on the other end may be electrocuted. Thank you." Hang up, and wait about two minutes. Call them back. When they answer, just scream "AAAAAAAAAAAARGH!!!" and hang up.
Get a few copies of your friends business card. Hopefully, it has his home phone number on it. Go to your local red-light district and pass them out to the girls (or guys) saying "Call me some time."
Hang a shower curtain out a window. When the person below reaches out and pulls it in, pour a bucket of water onto the shower curtain. Listen to hear the results. Requires a nosy neighbor below you.
Does the person that you want to get even with drink red wine? If so, get yourself some Neutral Red, a water soluble, crystalline, red dye. Mix some into the persons wine and wait for them to take a leak. (Nuetral Red comes out as red as it goes in, and people have a tendancy to get really nervous when they start pissing what they think is blood!
A popular college dorm practical joke involves collecting newspapers for about 3 months by everyone. When a guy on your floor has a three hour lab crumple up newspapers and completely fill his room from floor to ceiling.
Go to any gag store and get a fake plastic vomit. Put it in a drinking fountain. Wet it is amazingly realistic ...
Take an old windowshade, go to a gymnastics show or anywhere else where people wear leotards, wait for someone to do a split, and tear the windowshade briskly, making a very loud ripping sound ...
Go with a couple of friends, stand near some busy street corner, and take a great interest in some point near the top of a tall building, or maybe just up in the sky. Watch the reactions of people around you.
Go into your community bathroom/shower, fill your bathtub with hot water, empty a couple of bottles of dishwashing detergent into the tub, then drop in a few pounds of dry ice that has been crushed to small pieces.
Take the top off the toilet tank. Inside, there is usually a vertical plastic pipe about 1 inch in diameter. Going into the top of this pipe is a little plastic tube. Turn the tube outward and, if it is long enough, then put it toward the toilet bowl with the end just sticking out. Replace the tank cover, making sure that the little plastic tube is just sticking out. When someone flushes, the tube will squirt water.
This is a practical joke that can be done to a person while he/she is sleeping. If the person's hand is dipped in warm water, this causes a subconscious relaxation of the bladder and causes the person to wet his/her bed.
While your friend is sleeping put shaving cream in his/her hand and then tickle his face with a feather
Try taping a drunk to his bed. Get a large roll of masking tape and when he passes out wind it around him and the bed.
Put ambesol in your friends mouthwash.
If your friend is a sound sleeper superglue their male organ...to the inside of his leg.
Make a small, off-center hole in a can of shaving cream and then heave the can into the victims open door. As the pressure spews the cream out, it will spin the can and create a real mess all over the place. Make sure you close the door after throwing it into your friends room.
Put cherry Kool-aid in the shower head.
Baby powder inside someone's hair dryer, causing the CASPER THE FRIENDLY GHOST look is also a cute one.
Put Ex-Lax in your brownie mix and place the finished product on your coffee table when friends come over
You might need a reputation as an incorrigable joker for this to work. Just let the person know you are going to play a big one on him within 5 days. (Pick your time frame.) And that he will be powerless to stop you. If you do it right, he'll worry himself to pieces and make a fool of himself. Then DO NOTHING.
Put a very kinky ad in your local newspaper, which includes your neighbor's phone number -- "call any time".
During winter time in any part of the country where it gets really cold, take your victims mattress, soak in water until it has reached it's saturation level, then hang it outside until it freezes solid. Once solid, replace on the victim's bed and make the bed up to look like normal. Boy will they be surprised when they go to bed.