FORT LAUDERDALE, Fla. -

A megachurch is defined as having 2,000 members or more, and is becoming one of the fastest growing movements in contemporary Christianity.

Every week, thousands flock to non-denominational Calvary Chapel in Fort Lauderdale. 

The church sits on 80 acres and ever week, more than 20,000 worshippers fill the sanctuary. 

Most come hungry to hear a word of inspiration from Pastor Bob Coy.

“Most of the time, it's how can we find more seats and parking spaces, which is a good problem,” said Coy.

At Calvary Chapel, there's even an overflow area with television monitors set up, live streaming video the service. It takes 800 employees to make sure the church machine runs correctly.

Compare this place of worship to Lakewood Church in Houston, Texas.

It is the largest church in the United States with more than 50,000 members. Instead of a traditional church building, worshipers gather at a former basketball arena: the Compaq Center.

The man who leads this gigantic congregation is Pastor Joel Osteen.

"The message is very positive and hopeful. There are a lot of things pushing people down and we try to lift their spirits. Everybody needs that,” said Osteen, who recently announced an event his church is holding at Marlins Park next year.

Part of Osteen's popularity has been fueled by his books, best sellers bringing millions of dollars to his ministry. 

Osteen was recently in South Florida for a book signing.  Along with his message of hope, Osteen said television and computers have changed the game of outreach.  

But many critics say these mega churches are run more like Starbucks than a place of worship.

“I do not see it as a business. They may, but my thing is how can we help more people use our funds effective," said Osteen. "I do use it to grow membership but to grow what we have.”

Coy agrees, saying for him, it's not about the numbers -- it's all about providing people with a hope for their future.

“When it comes to goals at our church we have always played catch up with where god has been leading and adding,” said Coy.