Riddles for Middle Schoolers

I arrive before the party guests and tell them where to go. What am I?

Two doors have two guards. One guard always lies, the other always tells the truth, and one door leads out. You may ask either guard one question. What do you ask?

Three cups sit in a row. The first two are full and the third is empty. How can you make them alternate full, empty, full by touching only one cup?

You have 6 blue socks and 6 red socks in a dark drawer. What is the fewest socks you must pull out to guarantee a matching pair?

A room has no windows and no doors. Inside are a table and a mirror. How do you get out?

What comes once in a minute, twice in a moment, but never in a day?

What is the next number: 2, 3, 5, 9, 17, ?

What comes next: 2, 5, 10, 17, 26, ?

What comes next: 1, 4, 9, 16, 25, ?

What comes next: 1, 8, 27, 64, ?

What comes next: 1, 3, 7, 15, 31, ?

What comes next: 2, 6, 18, 54, ?

What comes next: 2, 3, 5, 8, 13, ?

What comes next: 1, 2, 4, 7, 11, ?

What comes next: 160, 80, 40, 20, ?

What comes next: 3, 5, 9, 17, 33, ?

What comes next: 4, 10, 18, 28, 40, ?

What comes next: 2, 3, 5, 7, 11, ?

What comes next: 1, 3, 6, 10, 15, ?

What comes next: 100, 91, 83, 76, 70, ?

What comes next: 1A, 2B, 4D, 8H, ?

What comes next: 12, 21, 13, 31, 14, ?

If A=1, B=2, C=3, what is CAT worth?

If A=1, B=2, C=3, what is DOG worth?