Entries in the events calendar that are marked as "Private" are missing some of their details when they show up (just as busy) in the public ical feed.
That causes the script to fail when creating the WeeknoteEvent. On line 42 of weeknote_event.rb:
html = html + "\n<td><a href=\""+ical_ev.description+"\">"+ical_ev.summary.gsub('"', '')+"</a></td>"
Because ical_ev.description is nil. summary is set to "Busy".
We should skip any such events, rather than crash 😁