- Rules for the Half-Masting of the National Flag of Canada - Super interesting! This page lists who's death warrants half-masting the flag, what happens to the national flag if a provincial flag is half-masted, what annual days are half-masted (April 28, Workers' Mourning Day; Last Sunday in September, Police and Peace Officers' National Memorial Day; November 11, Remembrance Day; December 6, National Day of Remembrance and Action on Violence Against Women; also on the Peace Tower only on April 9, Vimy Ridge Day; and for the duration of the annual Memorial Service on Parliament Hill to remember deceased Parliamentarians) and that the flag is half-masted upon the death of a member of the Canadian Forces who is deployed on operations to a special duty area (which was controversial a few years ago).
- Half-Masting of the Flag - This official pages lists why the flag was flown at half mast (2007-current), with no RSS feed though.
- Wikipedia: Half-Staff: Canada - This is a nice summary, and also includes information for other countries.
- Rules for Flying the Flag - Very interesting, and includes grainy black and white pictures!
- The National Flag of Canada - All you'd ever want to know about the national flag.
- Canadian Flag Etiquette - Tons of info about everything you ever wanted to know about the flag and flying it.
- Wikipedia: Flag of Alberta - Good ol'wikipedia gives us all you'd ever want to know about our provincial flag.
- To find out why the provincial flag is half-masted at the Alberta Legislature building, can call Visitor Services at 780-427-7362 or Legislature Information at 780-427-2826.
- School boards also have their own rules about half-masting and flag flying (eg. Edmonton Public, University of Alberta).
And yeah, just call the building if you're not sure why a flag is flying at half-mast, sometimes I forget people still use those things called telephones...