The 3 categories of shofarot that may be used to fulfill the mitzvah of tekiat shofar- the speech of Rav Kook on Rosh Hashana 1934 warning of the darkening clouds over the heads of European Jewry
Blowing a shofar into a pit- application to reading the megilla, reciting havdala, listening to shofar using a microphone, telephone or video conference, and hearing aids
The principle of 'ein kateygor naaseh saneygor'- the prosecutor cannot become the accuser- application to a Kohen who kills someone while driving- may they still give the Kohen blessing?