I assume it's blasphemy against the Holy Spirit, but I have no idea how I would go about committing that, so I should be safe for now. **Nobody tell me!**
I can't say with any certainty exactly what happens to people after death; however, I know as a Catholic that God does not condemn people who honestly seek Him in their way, no matter their religion (or even their lack of it). Probably, the unjust and wilfully evil will burn, and rich or hedonistic people will likely be sternly chastised. However, I cannot and will not believe that hell is eternal. All souls will in the end be gathered up under the Son.