What is in seasons, seconds, centuries and minutes but not in decades, years or days?

You can see it everyday, But cannot touch it at will. What is it?

Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

Twenty frogs are sitting on a log floating on the surface of a river. Two of them decide to jump off into the water.

How many frogs are there on the log at this moment?

Jenifer and Jesica are having a conversation.

Jenifer: I am definitely not over 30.
Jesica: I am 28 and you are surely 5 years older to me at least.
Jenifer: No, you are at least 29.

You are told that both of them are lying throughout in the conversation. Can you find their respective ages?

There are two dice with empty faces in front of you and a marker. You can mark any number on each of the faces of the two dice, but you have to display all 31 days of the month using the two of them.

Which numbers will you mark on which dice so that you can easily depict all the dates of the month?

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

There is a place where if I stand up straight, I will still be considered sideways.

What can you deduce from the following BrainBat?

CRY
LMKI