Check out this thread http://www.theyeshivaworld.com/coffeeroom/topic/interesting-facts-and-stories-about-our-gedolim
Additionally I have a gedolim story (or 2). I learnt in a certain yeshiva once. The Rosh Yeshiva gave(and still gives) shiur every day. One day he mentioned the Rambam in shiur and tried to say pshat on it. The next day, the first thing he said in shiur, “Right before I was going to sleep, I was thinking about the Rambam and I think pshat can be a little different than what I said yesterday.” Fr5om this I got inspiration. This is what a gadol thinks before going to sleep. That’s gadlus.
In a different yeshiva where I am learning now, A friend of mine told me a story about the Rosh Yeshiva (who was niftar not too long ago) My friend is a kohen. One day,as he was about to walk into the building of the yeshiva, he noticed the Rosh Yeshiva also about to walk inside. He stopped to let the Rosh Yeshiva in. The Rosh Yeshiva told him, ” You’re a Kohein, you go first.” My friend didn’t want to, he wanted to let the Rosh Yeshiva go first. The Rosh Yeshiva just stood there. My friend didn’t want to keep the Rosh Yeshiva waiting, so he ran inside. Later, he asked the Rosh Yeshiva, “The Halacha is that a Talmid Chocham comes before Kohen, so why did Rebbe want me to go in first.” The Rosh Yeshiva answered him, “I don’t understand you. I have a mitzva to be mechabed a Kohein, and you want to take that mitzva away from me?!”