Rabbi Yochanan ben HaChoranit Hosting the House of Hillel and House of Shammai in his Succot-Hut: Berachot 11a
The Students of Shammai and of Hillel meeting in the attic of Rabbi Yochanan ben Betairah: Menachot 41b
Rabbi Yehoshua once ruled according to the stringent view of the school of Shammai, and when his students complained that he was extending a period of discomfort for them, he responded that he was extending their share in the World to Come: Niddah 16b
The students of Shammai debated with the students of Hillel for three years, until a Divine Voice announced that although the words of both are the words of the Living Gd, the law follows the students of Hillel, due to their gentle humility: Eruvin 13b
Legal Issues
How to practice, when there is a disagreement between the house of Hillel and the house of Shammai: Eruvin 6b-7a; Pesachim 114a; Ketuvot 60b
The opinion of Beit Shammai is as nothing when it conflicts with that of Beit Hillel: Beitzah 11b