Yes with LAN. Just get your friend to open a single player world to LAN and then click on multiplayer and select his world
Chat with our AI personalities
First, go to the Minecraft folder. Go to the save files. Copy the world you want, and paste it back in. This will copy the world, and make a duplicate.
If you get bored of Minecraft, you can always download a few mods, get a new texture pack, or go on a server and play with friends.
Go to the %appdata% folder on your computer, then go to .minecraft, then delete the .bin folder.
go into the minecraft source file(windows=Run-%Appdata%-->.minecraft/mac=finder-->Username--> Library--> application support-->minecraft) then go to saves then your world and copy the level.dat file to the desktop. go to minecraft then put all items into your chest. save and exit, then quit minecraft.replace the new level.dat with the one on the desktop and there you go, duplicated items!
Take a look at the website called "Planet Minecraft", there are thousands of Minecraft resources you can browse and download If you have ever heard of the syndicate project, he has a pretty good world. Just search the Minecraft project and go to one of the episodes that is a multiple of ten.