1. Arjuna as an eunuch
In Indralok, Arjuna was propositioned by apsara Urvashi, but Arjuna addressed her as 'mother', Ur [Brihinnala] vashi was annoyed with the rejection and cursed him that he would become a eunuch. When Indra came to know about the curse, he told Arjuna that the curse would serve him as a boon during the one year stay in hiding and after spending that period he would regain his masculinity.
This proved to be significant in the war of Kurukshetra. After spending 12 years in forest, Pandavas spent the 13th year of exile in cognito, in the court of king Virat. Arjuna made use of the curse and lived as a eunuch named Brihannala.
2. Five golden arrows
As Kauravas were losing the battle of Mahabharata, Duryodhana approached Bhisma one night and accused him of not fighting the Mahabharata war to his full strength because of his affection for Pandavas. Bhisma greatly angered, immediately picked up 5 golden arrows and chanted mantras declaring tomorrow he will kill 5 pandavas with the 5 golden arrows.
Duryodhana not having faith in his words asked Bhisma to give custody of 5 golden arrows saying that he will keep them and will return them next morning. Long back before the Mahabharata war, Pandavas were living in exile in a forest. Duryodhana placed his camp on the opposite side of the pond where Pandavas were staying. Once while Duryodhana was taking bath in that pond, the heavenly prince Gandharvas came to take bath Duryodhana could not tolerate this and had a fight in which Gandharva captured him. On request of Yudhisthir, Arjuna saved Duryodhana and set him free. Duryodhana was ashamed but being a kshatriya, asked Arjuna what benediction of boon would he like Arjuna replied he would ask for the honour gift later when he needed it.It was during that night of Mahabharata war, when Krishna reminded Arjuna of his unsatisfied boon and told him to go to Duryodhana and ask for 5 golden arrows.
When Arjuna asked for the arrows Duryodhana was shocked being a kshatriya and bound by his promise he had to give those golden arrows. He asked who told you about golden arrows, Arjuna replied who else other than Lord Krishna. Duryodhana again went to Bhisma and requested for another five golden arrows. To this Bhishma laughed and replied this is not possible and will of Lord is Supreme and undeniable and whatever happens tomorrow in the Mahabharata war is written long before.
3. Birth of Drona
Drona was not gestated in a womb, but outside the human body in a droon (vessel). Bhardwaja went with his companion to the Ganga to perform his ablution. There he beheld a beautiful apsara named Ghritachi who had come to bathe. The sage was overcome by desire, causing him to produce reproductive fluid. Bhardwaja captured the fluid in a vessel called a drona and Dronacharya sprung from the fluid thus preserved. Drona would later boast that he had sprung from Bhardwaja without ever having been in a womb. Drona was the teacher of Pandavas and Kauravas and later fought the Mahabharata war from Kauravas side.
4. Lord Krishna broke his promise
Before the battle of Mahabharata, Lord Krishna promised that he will not pickup any weapon.On other hand, Grandsire Bhishma promised Duryodhana that he will fight like a lion and will kill Arjuna or will make Lord Krishna breaking his promise. There was an intense battle between Arjuna and Bhisma and Arjun being powerful still was no match for Bhisma. When Bhisma shot arrow which cut Arjuna armour and his gandiva bow. Arjuna was helpless before the wrath of Grand sire. As Bhisma was about to kill Arjuna with his arrow Lord Krishna could not tolerate his devotees plight and he immediately threw down the chariot rein and jumped off the chariot onto the battle field and lifted a chariot wheel and charged Bhisma determined to send him to death. Arjuna tried to stop Lord krishna but Lord says that in order to protect my devotee, I must break my own promise.
5. How Shri Krishna ended up on Pandavas side in Mahabharata war
Duryodhana and Arjuna both went to Dwarka to meet Krishna in order to seek his support for Mahabharata. Duryodhana was first to reach Dwarka. Satyaki informed that Krishna was asleep. Both Duryodhan and Arjuna entered Krishna's bedroom. Duryodhana who was first to enter the room sat on a seat at the head of the bed on which Krishna was asleep. Arjuna went to the foot of the bed and stood there with hand folded. When Krishna got up he saw Arjuna first who was standing at his foot. Duryodhana said that as he came first so it was fair that Krishna should join Kauravas.
On this, Krishna smiled and said as he saw Arjuna first when he got up so it is also fair that he should help both Kauravas as well as Pandavas. So on one hand was his famous Narayani army, and on other hand was he himself alone and shall not yield any weapon. Then he added that dharma demands that the younger should have the first choice. So Arjuna was given the first chance, he fell at the feet of Lord Krishna with tears in his eyes he chose him. Duryodhana was very happy with the decision. Shri Krishna later became the Arjuna's sarathi during the war of Mahabharat.
6. Yudhishthir firm adherence to truth
Yudhisthir was very well known for his firm adherence to truth. But, in the battle of Mahabharata, Drona, who was Kauravas commander was killing thousands of Pandavas warriors Krishna made a plan to tell Drona that his son Ashwathama has died, so that Drona would give up his arms and could be killed easily.
The plan was set in motion when Bhima killed an elephant named Ashwaththama and loudly proclaimed that Ashwaththama was dead. Drona approached Yudhisthir for confirmation because he was the only person who could tell him the truth.Yudhisthir who could not make himself tell a lie inspite of the fact that if Drona would continue fighting pandavas and the cause of dharma would have been lost. Yudhisthir added ‘praha kunjara ha’ which means he is not sure whether man of elephant has died. Krishna knowing this that Yudhisthir would be unable to tell lie, had all the warrior beat war drum and cymbals to make as much noise as possible so that the words ‘praha kunjara ha’ were lost. Drona was disheartened and laid down his weapons. He was later killed by Dhristadyumna.
After speaking this half lie, Yudhisthir feet and chariot descended to the ground.
7. End of Jayadrath
Jayadrath was granted a boon by Lord Shiva to hold the pandavas brother at bay for one day in battle – except for Arjun who was protected by Lord Krishna. In Mahabharat war, Jayadradth was fighting from Kauravas side, he using his boon to stop Pandavas from entering the near-impenetrable chakra viyuh battle formation. When Arjun son Abhimanyu enters the formation he was trapped inside and brutally killed. Arjuna vows to kill Jaydradth the very next day and if he failed he would kill himself. Arjuna killed an entire akshauhini during the day’s battle. At a climatic moment the sun had nearly set and thousands of warrior still separates Arjuna and Jayadrath. Seeing his friend’s plight, Lord Krishna send his Sudarshan chakra to mask the sun creating a solar eclipse thus faking a sunset. The Kauravas warriors rejoiced over Arjun defeat and his imminent suicide exposing Jaydradth from his hiding for a crucial moment. Upon the Lord’s urging Arjun shot a powerful arrow that decapitation Jaydradth. Jaydradth father was a sinful king he had pre cursed the killer of his son that anyone who caused Jaydrath’s head to fall on ground would suffer by having his own head exploded. When Arjun recapitulated Jaydrath he faced death but Lord Krishna intervened he asked Arjuna to shoot his arrow that would carry Jaydradth’s head to his father’s lap when he was sitting meditating in his ashram. Arjuna did the same and shot 3 arrows which carried Jaydrath’s falling head to his father’s lap. when he got up after meditation he didn’t see the head in his lap but caused it to fall on the ground so his head exploded as a result.