Just log it in your timesheet and carry on.
This answer is based on two assumptions:
- Your company uses some method to record time spent working on various activities.
- Your management routinely uses the data from such timesheets to monitor employee and company productivity.
First of all, note that there are potentially two orthogonal issues here:
- Non-productive meetings: If you feel that your presence at a particular meeting is utterly pointless yet you're getting invited repeatedly, just bring it up with the organizer to find out if you really have to attend and why.
- Too much time spent meetings:
If the situation that you describe happened in any of the companies I worked for, I would have just entered "Wednesday, 2 hrs development on Project A, 5 hrs meetings, 1 hr preparing slides for a meeting" into the web app/Excel sheet/paper form by the door and that'd be it. Management would then notice that overall time the company spends in meetings is up 1400% in a year and take action (or not, but that's purely up to them).
As the management already has a dedicated tool to track how much time is spent where, it doesn't make much sense to side-step such system. It's much easier to aggregate data and get a company-wide overview of the situation using a dedicated reporting tool instead of extracting peoples' impressions from a bunch of e-mails.
Additionally, numbers in an Excel sheet don't carry any implied feelings with them. Sending an e-mail that you spent 30 hours in meetings this week signals annoyance and unhappiness, writing "30" into a box does not. It's the best way to avoid coming across as trying to say "I don't like the way you run this place".
It also sounds like the organizational structure in your company is somewhat convoluted, so just e-mailing your boss might also not be the most efficient approach if your boss doesn't have any direct authority over the other people calling you into meetings. In contrast to that, the timesheet data might be reported to someone who actually has the authority to decide how much time is the company as a whole supposed to spend in meetings.
In contrast to this, the plan with the calendar doesn't sound like a good one. First, it does not make it any easier for the management to notice what is going on, so it sounds like just you trying to cover your behind. Second, it might be perceived as an attempt to publicly shame your coworkers for wasting your precious time. Whatever method you choose to communicate this to the management, keep it private.