this Instructable shows one how to make a fully functional hammock in under 5 minutes with household supplies.
Step 1: Materials
knife (Or anything that cuts)
10 feet of rope.
Step 2: Preparing the Sheet
cut the sheet in half lengthwise, or at about 2 1/2 ft from the edge if its not a twin.
Step 4: Finishing
the last step: tie to a tree and relax.
Note- it may look incredibly thin, but it will widen when your in it.