If you like the idea of creating your own theme-park, but you're looking for more exciting rides, you'll want to check out Thrillville: Off The Rails. It allows rides that are actually off rails; the developers call these "Whoa- rides." The height limitation on the coasters has been greatly increased. If coaster tracks aren't completed, then the ride ends in an explosive crash and riders parachute to safety. If you want to avoid the explosive end, it's easy to do with the addition of the new auto-complete feature that will finish out a coaster for you if you get bored with building your ride, but your coaster is not a completed circuit yet.
Thrillville: Off The Rails features more expressive visitors - you can talk to everyone in your theme park and get feedback on what they think of your theme park, if you decide you want to. You can choose the level in which you want to manage, whether it be micromanaging every last detail or just buying an existing pre-made ride and taking it for a spin. If, and when, you decide that you want to customize your rides, you'll be happy to see that everything is totally customizable. Obviously the roller coasters are, as you can build them from scratch, but even the other rides can be themed - not only be just selecting a theme, but by actually selecting and placing individual decorations from a theme where you want to place them.
Expect the thrills to start in October 2007.