This glitch requires the Jamaaliday calendar, only available in December.
Step 1: Make sure you have an item on trade, then log out and log back on (if you haven't received the calendar gift yet).
Step 2: Open the calendar gift but don't click on "Keep" yet.
Step 3: Get somebody to trade you a masterpiece and go to the artist's den.
Step 4: Rather than clicking on keep (which accepts the bows and arrows), click on the gift again as it is no longer grayed out.
Step 5: It will open the gift for a second time. When you accept the gift, the old gift becomes stuck on your screen and you can't click on "Keep" or "Discard". You are able to X out of the calendar once you have done this glitch.
Effects
Getting traded a masterpiece again (and going to the artist's den) or being locked out at step 4 will make you able to click on the gift for a 3rd time. The accepting the 3rd gift will make the 2nd gift get stuck on your screen. If you keep switching rooms, you can click on the same gift an infinite amount of times.
The gift that's stuck on your screen follows you into every room you go to, and can only get rid of by reloading.