Minecraft Forums

Don't get mad at me if this doesn't work. I thought of this just now and I can't test it atm.
First create a world and then save. Then click change save device and insert a USB in to your Xbox. Select the USB from the storage device list. Then take the USB to a friends house. At his/hers house plug the USB into their Xbox. Click change save device and select USB. The world should be already in the list of pre created ones.

Or upload the save to a file sharing site?

I guess you could do that. I'm going to try this later today and see if it actually works.