What do you do when you finish all the islands in poptropica?

Until the next islands come out, you can play the ad mini-games, and the Store games such as Haunted House and Earth Day, or play in the multi-player rooms.

You can also create a new username and play the islands again (but you cannot combine credits among users). You can restart an island (from the small map) and play it over again.

(see the related question)