Go to the sporting goods store and buy some collapsible 12 ounce can cozy's ... as light and thin as you can find.
Then pick up a P38 world war II type mini can opener.
On your way home stop and pick up a six pack of Hieniken cans (they have the distinctive barrel shape).
Go home, get comfortable, and have a Hienie .... while you're enjoying your second Hienie, take the P38 can openner and carefully cut the top out of the first can leaving the rim of the can intact. Rinse out the can with soap and water and dry.
Make sure there are no sharp edges then slip the can into one of the cozy's you bought in step one.
You now have a very sturdy (the barrel shape is very sturdy) 12 ounce insulated coffee mug/cup that weighs less than one ounce. (mine weighs 0.9 ounces).
You can make a second one, but I would suggest that you stop there and save the empties to work on tommorow.