BOULDER, Colo. - Celebrity businessman Donald Trump was again center stage as the Republican presidential field gathered Wednesday night for the third debate of the 2016 campaign, but for the first time, the billionaire seemed reduced to the role of a supporting cast member.

An early rumble between former Florida Gov. Jeb Bush and Florida Sen. Marco Rubio showed they were willing to fight for the spotlight. Retired neurosurgeon Ben Carson, the leader in some recent preference polls, stuck to his soft-spoken style, while Texas Sen. Ted Cruz had some highlight moments - especially early on.Here are a few takeaways from the two-hour matchup in the swing-state of Colorado.Bush, Rubio rumbleSimmering tension between Bush and Rubio, who are vying for the same traditional Republican donors and supporters, spilled into plain view just 15 minutes into the debate. Bush seemed prepared to go after Rubio for missing votes in the Senate, but appeared ill-prepared for Rubio's quick response - that he's only attacking him because he's behind."Marco, when you signed up for this, this was a six-year term and you should be showing up to work," Bush said. "I mean, literally, the Senate. What is it, like a French work week? You get like three days where you have to show up?"Rubio was ready with his reply, citing the percentage of votes missed by previous senators who ran for president, including President Barack Obama. The detail of his response showed he had been prepared for the attack.A quieter TrumpWith the moderators focusing more on Bush, Rubio and some others, Trump seemed unusually quiet.He was asked only a few questions by the moderators from CNBC and interjected himself into other questions far less than in the first debate. One of his longest responses was on his company's bankruptcy record.As has been the case on each of the crowded debate stages, some candidates - including Kentucky Sen. Rand Paul and New Jersey Gov. Chris Christie - seemed to disappear for long stretches of time.That was also the case for former Arkansas Gov. Mike Huckabee, though he jokingly compared the bloated federal government to a runaway blimp making news and later pointed out that he was wearing a Trump tie.Cruz pushes inCruz was a champion college debater and those skills were on display. He deftly recapped the moderators' quizzing of his opponents, describing those interactions as antagonistic.The rebuke drew some of the loudest, most sustained applause of the evening.Cruz said the Republican debate is a stark contrast with the Democratic contest, "where every fawning question" was about "which one of you is more handsome and wise?"Christie, Trump, Rubio and others joined in the media bashing. So did Republican National Committee Chairman Reince Preibus, who told reporters the moment the debate ended that he was disappointed in both the debate's moderators and CNBC.Cruz, a freshman Texas senator who has made his name by defying his fellow senators, also had one of the most memorable quips of the night. Asked by moderators to describe his worst characteristic, he said with a smile: "I'm too agreeable, easy-going."Carson quizzedDuring the August debate, Carson said at one point, "I wasn't sure I was going to get to talk again."This time, as the leader in some recent preference polls, the moderators showed that people are taking a closer look at his background and his policy proposals.Carson said he'd like to have an across-the-board tax rate of 15 percent and get rid of all income tax deductions and loopholes if he were president.He was questioned about his involvement with Mannatech, which is under legal scrutiny. Although he appears in promotions for the company, he called it "absurd" to say he has a relationship with them.