Riddle #660

Question: Christmas and New Year's Day occur exactly one week apart. So a New Year's that occurs right after Christmas should be on the same day of the week. But in the year 2020 Christmas will occur on a Friday and New Year's on a Wednesday.

Why is this?

Question: What tastes better than it smells?

Question: What goes in the water black and comes out red?

Question: What loses its head in the morning and gets it back at night?

Question: What two things can you never eat for breakfast?

Question: People see through me, but none pass through without killing me. I can be anywhere, and can be seen double or single. What am I?