Calendar surfing 

The act of looking through shared office calendars of other employees to find meetings to join even though you weren't invited. This is to fill up your own calendar and make it look like you're busy. At the meeting you're pretending to listen but just space out and nod once in a while to make a believable impression.

Johnny was calendar surfing yesterday, getting no real work done, just passing time at meetings.

Calendar surfing by TheManWithTheHarmonica September 15, 2012