Board Thread:Questions and Answers/@comment-70.225.44.18-20130615185508/@comment-24148835-20130615203919

Like it says on the page. You must complete an obstacle course. This stamp is really rare and hard since few parties have obstacle courses. But whenever there is a party with a obstacle course, then you must do the objective of the stamp to earn it. You must also become a member because like in the Adventure Party: Temple of Fruit the room with the obstacle course was for members only, there was no way else to earn it.

Just be patient, become a member if necessary and wait whenever a party has an obstacle course.