Move over Roller coasters and water slides, The latest trend is indoor trampoline parks. Charging fees of $8 to $14 an hour, there are approximately 50 parks in the US that feature wall-to-wall trampolines. The parks are exceedingly popular, with revenues approaching $100 million.Chains such as Sky High Sports, which currently has eight locations nationwide and plans to open three more this summer, are getting a piece of that financial pie. Co-owner Jerry Raymond opened the company after leaving his job in the computer industry, saying, “I was looking to do something where my kids wouldn’t be embarrassed to come to work with Dad.” But still, these parks are not without their risks. Injuries such as broken arms and legs and even a non-fatal broken neck have been reported. “We do not recommend recreational use of trampolines, as sad as that may be,” says Jennifer Weiss, an orthopedic surgeon at Children’s Hospital Los Angeles.