It started out, "Our 5th (of only 7!) meeting will be at ... ." I think this give a great sense of progress to the team, and a good reminder of the short-term nature of the project. Many of our teams could use the reminder that projects should have an end, and the meetings associated with them should also end.
The next line was simply, "We finish in 18 days!" It is very useful to get this reminder of where we are in the project, so we can gauge our pace against our progress. When the leader keeps people informed about key project dates, it lets the team better focus on their own tasks.
At the end, she added two action items for people before the meeting. This made the meeting more valuable for everyone. We are all used to sending out an agenda. Agendas tend to focus on what will happen at the meeting, but preparatory actions engage the team in the meeting's success.
One more thing added to the value of the meeting announcement. The entire message took up only eleven lines, including spaces. It all fit in the preview screen of a mailer. That meant it was short enough that people would actually read it.