Pens are items found in Poptropica.
Role on Reality TV Island
You must use a cheap pen to fill in a Reality TV application form. It can be obtained at the Wayside Motel Office.
Role on Great Pumpkin Island
Linus will leave a pen on his desk after he finishes writing his letter to the Great Pumpkin. Later on, you'll give it to Charlie Brown so he can sign Lucy's contract.