Kumbhakarna was the younger brother of Ravana, and the elder brother of Vibhishana. He was born huge and had a great appetite. He grew up to be a gigantic, powerful and strong Asura, but was very wise, of good character and a great warrior. Due to all these unique qualities, Indra and the other devatas in Devaloka were worried as Kumbhakarna would indeed be an undisputed winner if he waged a war against Indra.
All the three brothers wanted to acquire boons from Lord Brahma and become powerful. Hence for many years they meditated on Lord Brahma. Being pleased with their penance, Lord Brahma appeared and asked what they wished for. Indra was terrified at the very thought of Kumbhakarna asking boons. He knew that Kumbhakarna would be unconquerable if he received powers from the Lord. He prayed to Goddess Saraswati who is not only the giver of knowledge but also the bestower of speech. Indra prayed to Saraswati to manipulate Kumbhararna’s speech while asking for a boon from Lord Brahma.
Kumbhakarna wanted to ask for Indrasana (throne of Indra) but ended up asking for Nidrasana (state of sleep), and instead of asking for Nirdevatvam (non-existence of Devatas), he asked for Nidraavatvam (continuous sleep)! The boon was granted. It was then that Kumbhakarna realized his mistake and requested Lord Brahma to undo the boon. But once granted, the boon could not be reversed. Hence, Kumbhakarna slept for six months and when he woke up, he would eat to his full for a day and again go back to sleep for the next six months.
During the fierce battle between Lord Rama and Ravana, Ravana’s army suffered great loss. At that time, Ravana decided to wake up Kumbhakarna. It is said that a thousand elephants were required to wake him up. When Kumbhakarna realized that Ravana had captured Rama’s wife Sita, he tried to convince Ravana to return Sita back to Rama. But Ravana was stubborn and refused. Kumbhakarna finally went to the battle field and after a fierce battle between him and Rama, Kumbakarna was finally killed by Lord Rama.
We are 'asleep' to the Great and Divine Presence in our bosom; the Wise-man never 'sleeps' like us!! - Swami Chinmayananda
[PS: I request all to please forward and share these value based stories rich in our culture and tradition to elders, youth and children]