50 (9 oz.) Solo Clear plastic cups (short squat ones)
1string 50-light set
100 paper fasteners
24-inch coated wire or heavy duty fishing line
Garland (optional)
Hole punch or small pointed soldering iron
Drill and bit (size depends on size of mini-light base)

Drill holes in the bottom of all 50 cups. Take 38 of the cups and put 2 small holes near the rim at the top (not needed if hot gluing), opposite each other.

Put the remaining 12 cups to one side for now so you don't mix them up. Do not punch holes in these cups yet (other than the one you already have in the bottom). For reference this will be called the "unpunched cups"

Work on one side of the ball at a time, take 12 of the cups and the paper fasteners and fasten cups side by side. By the time you get to the 12th one, it should form a circle. Complete by attaching together. Set aside.

Take 2 of the unpunched cups and punch one hole near the rim. With 7 punched cups, fasten together side by side. Take each of the 1 hole punched cups and attach to each end of the 7 attached cups. Take the 2 one hole cups on the end and bring them together, forming another circle, that will arc out, punch hole in both of these one hole cups where they meet and fasten together. These 9 cups should fit on top of the 12 previously fastened cups. With the hole punch, fasten the 9 and 12 grouping cups together. Take 4 unpunched cups and punch 1 hole in each near rim. Fasten 2 of these cups together. Fasten other 2 together. Set these on top of the hole left in the 9 cup grouping so they fit. They will not be exactly opposite each other. Make holes in each of the cups where they join the 9 group. Fasten together. This should form half of the ball. Repeat to form other half.

Adding the Lights

(Holes should have already been drilled in step 1.) With the open end of ball facing you put the light on the string ( opposite end of plug) in one of the holes in the 4 center cups. (At this point, begin putting garland along the wire by looping it over the wire between each light, it helps hide the wire .) Continue until lights have been put in all 25 cups.

When you do the other half, start with the light closest to the plug and put that into one of the 4-cup cluster and work your way out. The last one will be a little hard to do since there isn't much wire to work with. Make sure plug and lead in wire are outside the cups, and set the first half on top of the second half fitting into each other. Punch holes where cups touch and fasten together. Where wire comes out, put 2 more holes in the top of two joined cups. These holes will be your hanger. Thread coated wire, or fishing line through these and make a loop to hang the ball with.
Tie the wire and hanger together near the cups with red velvet ribbon if desired. Some also make these with the top 4 cups omitted, and figuring out another way of hanging it, probably a hole put on each side of the ball and 4 lines coming up to hang it with. Fasteners take longer, but the ball is sturdier.

You can also make half balls the same way as the full, only use 35-light sets and the 4 cup cluster has 2 holes each and 6 of 12 cups have 2 holes (every other one). To finish off back, put a plastic 12-inch plate and fasten it to the back with the bottom of the plate to the inside near the wires. These half balls can be placed flat against walls.