Delivery Notification
You can arrange a pickup of your sword in Rivendell between the hours of noon and 7:00 PM.
You can arrange a pickup of your sword in Rivendell between the hours of noon and 7:00 PM.
In the US, when the package delivery company UPS (or other package delivery companies) knocks on your door or rings your doorbell and cannot reach you, they leave a delivery attempt notification stuck to your door. These may be for packages that require a signature, such as expensive electronics. An example is shown in the first panel.
This comic hints that the threshold for the UPS delivery person to leave such a notice is unreasonably low. The delivery personnel made only a token effort to deliver the package (which, incidentally, is their only actual job) before posting the yellow delivery notification and unconcernedly driving away to their next delivery (or, more likely, their next yellow-delivery-notification-posting).
After missing the delivery, Cueball (who is directly referencing The Lord of the Rings) asks the Elves to reforge his sword in order to go on a quest to retrieve his new laptop. In The Lord of the Rings, Aragorn (accepting his role as the heir to the king of the West) had the sword of Elendil, called Narsil, reforged (which symbolizes the reuniting of the race of man under one leader). Cueball obviously views the UPS building as a dangerous and impenetrable fortress, and possession of such a sword is the only way to guarantee success in his quest.
Ironically, when the Elves come to deliver the new sword, the delivery elf is unable to notify anyone in the house, and simply leaves another delivery notification.
In the title text, Rivendell is one of the home of the Elves, where the broken shards of Narsil resided, with Elrond and his elves. Unfortunately for Cueball, the sorting depot of Rivendell has the same, limited opening hours as the UPS. It is apparent that Cueball will not be getting his laptop in time for his flight.