We love our skylights but they are southern facing and really heat up the house in the summer and make it impossible to see the TV during the day. I came up with this idea a few years ago and finally took pictures as I installed it this year.
Note: Our skylights have a beam that supports the weight of the shade. If your skylight does not have this you may have to add something like fishing line to support the shade down the middle of it.
Step 1: Materials
(1) Light filtering temporary window shade (wider than the size of your skylight)
(1) Clear plastic corner guard for drywall (twice the length of the vertical measurement of your skylight)
(3) Command Brand adhesive strips
You could get the Light Blocking shades but we prefer the filtering ones. It still lets in enough light during the day but keeps the room MUCH cooler.