well in theory it would sound pretty awesome but in practice it can be quite difficult. I'm not saying because of the amount of fear you might have when going on it stoned but rather because you're high would probably wear off by the time you got on the rollercoaster. I mean think about it....you and you're friends smoke right before you get there then you wait in line for at least 10 to 15 minutes, then you finally have to locate a coaster and wait in line for another 30 to 45 minutes in line so by the time you get on it at least half of your high is gone so its not as awesome. But if you went on a really good day timed the smoke session just right, and brought along some brownies, it could work but still, it would be tough regardless. The only other way I could see it working in your favor is if you went to a local fair and they just happened to have a rollarcoaster but even then you're probably gonna get the crappy coasters.