Release a bunch of balloons into the air. They'd float to the leak. If you want to get fancy, coat them with a glue that bonds to the ceiling material, and the

Release a bunch of balloons into the air. They'd float to the leak. If you want to get fancy, coat them with a glue that bonds to the ceiling material, and they'd fix the leak too! At least temporarily. My first thought was that they'd clog the hole automatically even without glue, but I think the pressure differential would just squeeze them through.