Step 1: Materials
Step 2: Case
Cut out a piece of cardboard that is 11" by 7.5". Fold it in half. Now, coat it in duct tape. Make sure you fold the cardboard tightly so it will stay closed. Or, you could add some wire to make a latch.
P.S. You may need to double coat the cardboard, so you can't see through it.
Step 3: Memory Card Slots
Take a piece of duct tape that is 5 inches long and lay it sticky side up. Now put a piece of duct tape that is 4 inches long on top of the other piece so that the sticky sides touch, but leaves some extra tape on the ends. Take this and lay it sideways on one side of the case. Stretch it just tight enough so that the memory card will stay. Repeat for the second slot.
Step 4: Disk Slot
Using the same idea as the previous step, make a slot for the disk. Make sure you tape the bottom so your beloved Halo doesn't fall out.
You're done. Hold all of your favorite games and precious saved games in this simple case. One idea I had but never actually made was to use some wire to make a latch to keep it closed.