Dig a hole in their basement and tunnel to another friends house, replace all the chest contents into the other friends house making it look like they stole them. It would be funnier if you move both of theirs. And then make another tunnel to ANOTHER friends house.
This is something I made in my own server. It is very hard to explain, so I will post pics in a few minutes. But aside the pictures, here are the basics. You need a hallway about 10 blocks long, 1 block wide, and 4 blocks tall. Deep inside your base, have this hallway and a button at the end of it (OPTIONAL: Have a sign on top of it saying "DO NOT PRESS") Someone will press it, and out of the wall shoots about 10 pistons with the block that holds the wall. These pistons need to be at head level (2 blocks high), or people can escape the trap. The button needs to be 3 blocks high or 1 block high, with the optional sign at 3 or 4. An RS-NOR latch keeps the pistons active, and powers about 200 redstone repeaters all at 4-ticks behind it, leading to the back of the RS-NOR latch. This will release the trap after about 1-2 minutes (Enough to kill anyone with diamond armor on peaceful). Be careful, if the trap is activated again before all the repeaters go out, the trap will either not activate, will last a fraction of the time programmed, or the torch will burn out (all have happened in the past). As said before, pics will be here in a few minutes to clear some things up.
Pics are here :smile.gif:
Here's a hallway
When they press the button...
Here's the redstone diagram in the off state
And in the on
And back to the off
Guess what? It's a pic of all the repeaters
Here's the diagram of the pistons in the off state (I shortened it for the sake of a secret door I had)
Once, I dug a small deep shaft. At the end of the shaft, I did some piston redstone inverter stuff so that when a certain redstone torch is destroyed, two sticky pistons holding stone seal of the shaft. The block that will activate it was a diamond block. I hid everything, and put a sign under the diamond block that said this:
I have something for you. -Herobrine
I got like 4 people in there at once, someone tried to take the diamond block, the shaft closed, and they all freaked out. It was hilarious!
today i rigged my skytram to drop my friend into lava unexpectedly using pistons.we have a bunch of huts built along the skytram, and i made it so one of the huts was activated by a pressure plate, which removed the blocks from under you and makes you fall into lava. its hilarious.
and i am totally copying his house somewhere else.
but you guys definitely need to try using dirt to cover up a house to make it look like part of the landscape. its funny as crap.