Reminding Rav Yosef of a lesson he had taught before his amnesic illness: Pesachim 13a
Raveina and Rav Ada bar Matna asking Rava a question, and entering a Synagogue for shelter so that they could study further: Megillah 28b
Once, Rav Ada bar Matna went to study and his wife asked him, "What should I for the children?" He responded, "Are there no more greens in the meadow?": Eruvin 22a