It doesn't take long to do enough research on the internet to discover the secret teachings of Scientology, that an evil alien emperor named Xenu dumped countless alien prisoners in a volcano on earth billions of years ago and that the ghosts of those prisoners attach themselves to humans, causing all of our worldly problems. For a price, the church will help you rid yourself of these "thetans" so you can live a perfect life. The whole story is so ridiculous, they only teach it to the very highest ranking members of the church because they know that if they led with it, nobody would ever join. They would just laugh and spend their money more wisely.
Scientology attracts rich and famous actors, most notably Tom Cruise, Kirstie Alley, Nancy Cartwright (voice of Bart Simpson), John Travolta, and many others. There's a list here if you want to see more. These people pay huge amounts of money to the church to fund its missions all over the world, including Sea Org, a fleet of ships on which members pledge their lives by signing billion year contracts to live and work extremely long hours (100+ hours a week) for very little pay.
Many would characterize Scientology as not so much of a church as a cult of hypocritical con artists who engage in the enslavement of humans while preaching that people are immortal beings with infinite potential. It can also be described as an atheistic religion. While they do believe in spirits and the supernatural, nowhere in their teachings is the worship of a god unless you count L. Ron Hubbard, the church's founder, as a god. They don't call him one though. Few atheists would be willing to count Scientologists among their ranks, or members of any religion for that matter, but if one is to be intellectually honest, one must acknowledge that atheism is only the absence of a belief in the existence of gods. It doesn't matter what else a person believes or doesn't believe.
The church of Scientology has a mission in Houston for those who want to visit and find out what they claim to be about. Just don't ask them about Xenu. That upsets them a lot, and it might make them try to sue you. Really. Scientologists are insanely litigious. They might even attempt to take down this article. They relentlessly harass ex-members (there is a message board here for ex-Scientologists), outspoken critics (as seen in this video), and journalists (see this video) looking into their organization. Like the Westboro Baptist Church, they are experts at using the legal system to get their way.