LHO hosted a public event this afternoon.  Arrival time at LSB = 1:00 - 2:30 PM PM.  Departure time = 3:00 - 5:00 PM.  Group size = ~170 adults/children of all ages.  Vehicles at the LSB = ~50 passenger cars (very uncertain).  A series of three walking tours between 3:00 and 5:00 brought a total of ~120 people into the control room during this time span.