Listen to tonight's class, "Key Cards on Shabbat," here.
Follow along with the sources here.
Listen to tonight's class, "Rosh HaShanah: Returning to Potential," here.
Listen to this morning's class, "The 'Written Words' of Halakhah (5)," here.
For further research:
Listen to our class on "Reading Secular Books or Newspapers on Shabbat" here.
Listen to tonight's class, "Elevators on Shabbat," here.
Listen to this morning's class, "Continuing the Oral Torah (4)," here.
Listen to this morning's class on Nefesh HaHayim 4.10 (1) here.