Because Nagato had bit her and put a chip inside of her to stop her from revealing any classified information to Kyon.
Because Haruhi wished it to be so, so it happened.
Her future-self makes her fall asleep so she can speak to Kyon without the past-Mikuru finding out she is there.
Because Mikuru was tired. She has a secret crush on Kyon and thought this was here chance.
Etisuki, Nataioko, Okunisan and Zoyoto
Enomoto, Nakanishi, Okajima and Zaizen
To get rid of him. She thought he might endanger Haruhi.
To see how Haruhi would react.
To see what his insides would look like.
To show the Data Integration Thought Entity that she was capable of killing people and making decisions by herself.
They went to a public swimming pool.
They went fishing in a brook neir Yuki's apartment.
They went to a cinema and watched old movies.
They had a bug contest where they had to catch one specific bug.
They had handed out balloons in frog costumes at a store.
They went to a shop and bought dresses.
They went to a homeless people shelter where they handed out soup.
They went to a fair where Mikuru and Haruhi went goldfish skooping.