Every day will be a birthday party at Six Flags Over Texas this year. Workers are hanging festive banners, painting bulls for a new ride and rehearsing for a nightly parade as the Arlington theme park prepares to open for its 45th season Saturday. "We have activity going on at the park seven days a week getting ready for the opening," General Manager Steve Calloway said. And while the park does not have a new roller coaster or thrill ride this year, it is unveiling 10 family-friendly rides and several new attractions that it hopes will entice visitors to celebrate with Six Flags: