Gaandhaaree was a very powerful woman among all the women of Mahaabhaarat. She was the wife of Dhritraashtra and mother of Duryodhan, Dushaasan etc 100 sons. Bheeshm specifically selected her as the wife of Dhritraashtra. As soon as she heard that her husband Dhritraashtra was blind, she tied a cloth strip on her eyaes for her whole life saying - "Whichever world my husband cannot see, I have no right to see that world."
In fact she was the only powerful woman whom we see as a boon giver and a curse giver, even to Bhagavaan, in the whole epic. There are very few people who can curse Bhagavaan and one of them was Gaandhaaree. (see Curses to Vishnu) She had a great will power too. It was only her will power that she stayed blind by tying a cloth strip on her eyes. No other such example like this is available in our scriptures. Who has good eyes and if she lives like a blind for her whole life just for this reason that her husband cannot see, is an outstanding example of being Pativrataa. Here I would like to cite three examples of her boons and curses.
Boon to Duryodhan
Although her whole life passed in making Kaurav and Paandav even, but when she had lost her 99 sons, and according to Bheem's vow, Bheem kiiled them all, she had no doubt that he would kill Duryodhan also by breaking his thigh according to his vow. She loved Duryodhan very much, and otherwise also wanted to save him. So she calls him and asks him to come to her naked after taking bath in Gangaa River. Duryodhan goes to take bath in Gangaa River and comes back.
While he was coming back, he meets Krishn and Krishn asks him that where was he going to at such odd time? Duryodhan says - "My mother has asked me to come to her naked after taking bath in Gangaa River. So I am going after taking bath in Gangaa River."
Krishn asks - Naked? Why?"
"I don't know. That is what she has said."
"Will you go naked in front of her?"
"Yes, That is what she has said."
"But you are adult, how can you go to her naked?"
"But she said that "I am your mother, what kind of shyness from mother?"
"But now you are adult. It is not proper to go naked to her. At least tie some cloth around your loins, after all she is woman." and Krishn goes away after advising him thus.
Duryodhan understands the logic and when he goes to his mother, he ties a cloth around his loin and when Gaandhaaree asks him - "Have you taken bath in Gangaa River?"
"Are you standing naked in front of me?"
She says - "Now I will remove this cloth strip from eyes and I will see you for the first time." And she removes the cloth strip from her eyes. A light comes out of her eyes and falls on Duryodhan's body. In a few moments his whole body becomes of iron. When the effect of her eyesight is over and she sees him normally, she finds that he had covered his loin part with a cloth. She breaks into tears and says - "You did not listen to me. Now nobody can save you from Bheem. I have earned this power after doing Tap for so many years. This could make your whole body of iron, and Bheem could not have broken your thigh and kill you. Since you have covered your thighs, now your thighs have remained weak and I am sure that Bheem will kill you by breaking your thigh." the same thing happened. When Bheem and Duyodhan were fighting, Bheem was not able to hurt Duryodhan's body. Later he had to break his thigh
Curse to Krishn
When the whole war was over, Krishn came to her to take leave. Gaandhaaree was very sad. She said to Him - "O Krishn, You could have stopped this war if you wanted, but you did not want it to be stopped. If you had stopped it, my 100 sons would have been alive and I would not be weeping for my children. Since you did this deliberately, I curse you that your own Kul (whole clan) should also die in the same way fighting with each other." Krishn smiled and accepted her curse and went away. Same thing happened as Gaandhaaree cursed Him. His whole clan got killed by fighting among themselves.
Curse to Yudhishthir
The third incident is not of curse by speech as such, but her sight, even from behind the cloth strip was enough to do it. It happened when the war was over, and Paandav met her in the battlefield. Although Gaandhaaree was very composed at the time of meeting them, but still she was very angry from inside. Although her eyes were still covered with cloth, but when Yudhishthir came to see her, she.looked at the nails of his feet and Mahaabhaarat says that because of her anger, his nails became blue.
Thus we find these three incidents of her boons and curses, including Bhagavaan.