Shemini Bulletin in PDF format

After one responds to Barchu, he may sit immediately; there is no need to remain standing while the chazzan  repeats the response.

There is a long long list of possible aveiros that Nadav and Avihu did to deserve their punishmen ; the bottom line is, though, that they behaved cavalierly in a mokom kadosh, the House of HaShem. Food for thought.