It is our great Sanskriti that we always regard our elders, whether they are our parents, Guru, relations or even an XYZ in the world. Many times we do some extraordinary acts also for them to show our love and respect. In every Yug such people have been born who have dome some extraordinary for their elders. Here I site three such examples who have done some extraordinary for their parents - one from each Yug, one from Sat Yug, one from Tretaa Yug and one from Dwaapar Yug (we are living in Kali Yug).
Prince Puru and King Yayaati
There has been a king in Sat Yug in Chandra Vansh (Moon's lineage) named Yayaati. He is the 7th in Brahmaa's lineage. He was married to Daitya Guru Shukraachaarya's daughter Devayaanee. Incidentally Daitya King Vrishparvaa's daughter came with her as her maid. When Shukraachaarya Jee married his daughter to Yayaati, he took a promise from him that he would not take any other woman to his bed. When Yayaati had children from Devayaanee, Sharmishthaa also expressed her desire to have children from him. Considering her request proper, he fulfilled her desire, so she also had two sons from King Yayaati.
When Devayaanee came to know that her husband had children from her maid, she filled with rage and went to her father's house. Yayaati loved Devayaanee very much, so he went to Shukraachaarya Jee to bring her back. Shukraachaarya Jee said - "My daughter's happiness is my happiness." and he cursed him to become very old for the rest of his life. First Yayaati got very troubled with this curse, but then he said - "But it will affect your daughter too." Then Shukraachaarya Jee relaxed his curse that he could exchange his old age with the youth from anybody who was ready to give him his youth.
Yayaati had five sons - three sons from Devayaanee and two sons from Sharmishthaa. First he asked Devayaanee's sons to lend him their youth as he was not satisfied with his life yet, but all refused to give it to him. Then he asked the same from Sharmishthaa's sons. One of them refused but the youngest son Puru got agreed readily and he said - "What other thing could I desire in my life than to fulfill the desire of my father." And he gave his young age to his father in exchange of his father's old age. With the youth of his youngest son Yayaati enjoyed his life for many years to come.
Raam and Dasharath
The second example is from Tretaa Yug. There was a King in Soorya Vansh in Ayodhyaa named Dasharath. He had three chief queens - Kaushalyaa, Kaikeyee and Sumitraa. With great efforts Dasharath had four illustrious sons from his these three queens - Raam from Kaushalyaa, Bharat from Kaikeyee and a twins Lakshman and Shatrughn from Sumitraa. As Raam was the eldest and all qualitative, Dasharath loved Him most. When He grew up Dasharath wanted to appoint Him as the Crown Prince. As all queens heard about this they were very happy,
But Kaikeyee's maid Mantharaa had something else in her mind. She went to Kaikeyee and asked her to ask her for the two boons, which the King asked her to ask for in the past and Kaikeyee deferred them to for some other time. When King came in the evening Kaikeyee reminded him of her two boons. The King remembered his promise so he readily asked her to ask for those boons. Kaikeyee asked Bharat's coronation as the king of Ayodhyaa as her first boon and Raam's exile for 14 years as her second boon. The King said to her - "I have no problem in giving kingship of Ayodhyaa to Bharat; but please do not ask me to send Raam to exile. What bad he has done to you? You loved Him more than Bharat, then what has happened to you today? Why do you want to send Him to forest? I cannot live without Him, I will die. And you are mistaken, even your Bharat will also not live without Him. Ayodhyaa people will also not live without Him. Do you want to rule empty Ayodhyaa?" But Kaikeyee simply refused saying that if he did not grant her these boons, he will be attached to the sin of breaking his promise. So Dasharath had to agree what she said.
When Raam heard about this, He said - "Fortunate are only those sons who get the opportunity to serve both their father and mother. I will surely go to forest to keep my father's promise to my mother." When Seetaa and Lakshman heard about it they also followed Him. That is how He served his parents.
Bheeshm and Shaantanu
This third example is from Dwaapar Yug. There lived a King named Shaantanu who ruled Hastinaapur (near Delhi). He married Gangaa on a condition that whatever she would do he would not ask anything from her about it; and the day he would ask her, she would leave him after answering his first question. He had 7 sons from her to whom she drowned in Gangaa River. The King noticed that she had drowned his 7 sons alive in the river. He got very much frustrated and worried but could not say anything because he did not want to separate from her as he loved her very much. Then he had the 8th son and when she went to drown that child too, the King could not stay silent and asked her why did she want to drown him?
As the King had broken his promise, Gangaa answered his question and went away to Heaven. She took her son also along with her to bring him up and get him educated. After 16 years she brought him on the Earth and handed over to Shaantanu. Shaantanu was very happy to get his son back. He appointed him as the Crown prince of Hastinaapur.
One day Shaantanu saw Satyavatee, a fisherwoman, and fell in love with her. He wanted to marry her but she told him that he had to ask from her father. He went to her father who told him that although there was no better groom than him for his daughter, but her birth chart said that her children will rule the kingdom; and since he had already appointed Devavrat as his heir, how can he marry her to him? The King refused to snatch the rights of his son from him and came back to Hastinaapur disappointed. He got very sad.
One day Devavrat noticed it and tried to know the reason of the sadness of his father and came to know about Satyavatee. He went to her father and asked her hand for his father. The fisherman told him the same thing what he told to the King Shaantanu. Devavrat said - "You asked a wrong person to give you the thing which is not his, how could he give it to you? "Why?" Devavrat said - "He has already given the kingdom to me, how could he give it to somebody else? He cannot give you the thing which is not his. Since the kingdom is mine now, I can give it to you. So I renounce this kingdom for Satyavatee's children. Now you marry Satyavatee to my father." The fisherman was still not satisfied, he said - "Tomorrow you will be married, you will have children, and if your children will claim their kingdom, then?" At this Devavrat took a great vow - "I take a vow today that I will not marry my whole life, I will live live bachelor, and I will die bachelor."
Now there was no doubt in fisherman's mind, so he had to marry his daughter Satyavatee to Shaantanu. When Shaantanu heard this he felt very very sorry for his eldest son, he then granted him the boon of Ichchhaa Mrityu - that he would die only whenever he would want to die." Since then he was known as Bheeshm.
That is how these three great personalities served their parents and considered themselves fortunate.