You print out a schedule or calendar and get everyone to stamp the days that they're unavailable. The person in charge of organising the event or party uses this to work out a suitable date. In this case, the party is being held to welcome me into the department I've been newly assigned to. Whenever someone enters the company or moves to a new department, this always happens.
All of the official documents come round on clipboards just like this one. In those cases, the contents are obviously a lot more serious and formal. Once everyone has read it and approved, it usually goes up to the CEO and when he stamps it, it comes back down to us mortals and we file it away.
