These are a favorite among many when it comes to ugly Christmas sweaters. They are especially popular with children it would seem,. There are several options when it comes to these. The lights can come from any number of sources. They can be stars, snowflakes, xmas tree lights, Rudolph’s nose, or even all of the above (white space is anathema to an ugly sweater!). There aren’t many rules to light up sweaters other than a preference of dark colors. The lights (usually) contrast better against darker-colored sweaters. Also, LED lights are often (but not always) preferable. Much of this depends where you’re going to be sporting it. These sweaters are best in low lighting where they stand out the most. But don’t overdo it by blinding your fellow party members!