The party comes across a magic amulet. This amulet will give each user two wishes, but the wishes almost seem to have a mind of their own.
Missions for any campaign in any city of any realm. As long as crime exists, you will be able to use this submission.
It is possible to buy magical abilities. The process is very dangerous though, involving chemicals, rituals and surgery possibly leaving the aspiring mage insane, retarded or scarred for life.