Here is a version which uses OSX's say command for a spoken announcement of "github is up again". It also checks once every minute instead of once a second.

    while true; do curl -s https://status.github.com/api/status.json | egrep 'good|minor' && say -r 160 "github is up again" || echo -n .; sleep 60; done

Edit: accept a status of minor as an indication of up-ness.