Hey, there's a indie game on Xbox 360 called Concept Coaster Craft.
It's $3.
Basically, it allows you to build and ride your own roller coasters in several different settings.
You are limited to sit down steel coasters and sit down inverted steel coasters. However, you can change the train type and allow for a flying coaster, or a spinning car coaster.
For $3, this isn't a bad game on the 360. Sure it isn't RCT, NL, or any of those other more advanced games, but it helps to quell the coaster fever during SFGAm's off season.
I have built around 15 coasters so far, some of them are SFGAm re-creations (I did do I best to accurately re-create the layouts - BTR, RB, SUF, ShockWave) and others are my original creations. You can download other people's coasters, and share your own creations with other people. If you want to download my coaster creations, along with the SFGAm coasters I tried my best to re-create, then my gamer tag is: D3R Meister.
Xbox 360 owners, have you tried it?