Russell Crowe has been hanging out with a crowd of friends in the courtyard of the Greenwich Hotel in TriBeCa, drinking amid the wafts of smoke coming from suspicious-smelling cigarettes and singing songs accompanied by an acoustic guitar, writes The Post’s Richard Johnson. The actor was lead singer for rock band 30 Odd Foot of Grunts, which evolved in 2005 into the Ordinary Fear of God. “Crowe is in the courtyard every night with his bandmates playing music. They’re not bad,” said one neighbor who also noticed a very distinctive fragrance wafting up from the courtyard. The hotel’s co-owner, Robert De Niro, has been informed of the situation and “he’s not happy,” said a source. Reps for Crowe, De Niro and the hotel had no comment. Crowe has gotten in trouble before in downtown hotels. In 2005, the thrice-Oscar-nominated star was charged with assault after he threw a telephone at an employee of the Mercer. Crowe, who avoided jail, later described it as “possibly the most shameful situation that I’ve ever gotten myself in . . . and I’ve done some pretty dumb things in my life.” For those of us who don’t have a window on the Greenwich Hotel courtyard, Crowe shows off his vocal talents as Inspector Javert in “Les Misérables,” opening on Christmas Day.