It has come to my attention that there are apparently people out there who do not really understand what a prank is. (Ahem)
Dictionary.com defines a prank as: "A mischievous trick or practical joke." Now I see how that could be misleading, especially with shows today such as "Punk'd" and "Overhauled" where it is considered funny to convince people their vehicle has been stolen. (I'm not saying that can't be funny, I'm just saying that's a big one).
So, I think maybe some guidelines or parameters are in order.
*A prank should be funny.
It may not seem funny to the prankee at the time, but it should be something that by the time it is being retold, should be funny. Compare:
1. So, we set this church on fire and it burned down. (Not funny)
2. So, we put thirty for sale signs in front of the school. (Funny)
*Know your target.
First - you should actually know the person you are pranking - or have the involvement of the someone who does (same rules if it is a place). This is also important because the bigger the idea is the more important it is to know if this person will sue you or have you arrested. (This is the world we live in guys).
So if (for example) you build an indoor pool, your targets need to find this funny. If it's more along the lines of a whoopee cushion thing this will be less crucial.
*It needs to be fixable.
Anything that causes permanent damage is not funny. There might be little leeway along the lines of we painted the roof, but not really, as long a the roof can be painted back. Which brings us to...
*You need to then clean it up.
If you turn someone's office into a beach (hilarious, by the way), you need to also be willing to clean it all up after everyone has had their laughs. If you are not willing to do that, then you might want to stick to something more along the lines of salt cookies instead.
Standard Disclaimer: I take no responsibility for any consequences should you decide to re-enact any of the examples listed above.