ocalhoun's creating a really neat scenario pack for Roller Coaster Tycoon. I've been slowly playing through it, but finding the indivdual scenarios has been cumbersome. So until they're complete and they're released as a complete thing, here's the list mostly up to date:
There seems to have been some problem with communication in your theme park management firm. The engineers gave you blueprints for all the latest and greatest roller coasters, but the marketing department gave you a park marketed and themed for small children. It's up to you to make this work.