OMG!  My girlfriend is too nice to write a review of the horrible experience that she is having today, so I am writing it for her.  I just cannot believe the behavior of a major airline and their horrific service.  \nMy girlfriend planned a short vacation for herself and 2 children to see Mount Rushmore.  She used Travelocity, which offered the United transportation.  They were supposed to leave at 6:15 AM this morning from McCarran Airport, but the flight was cancelled.  Why?  She was told that the flight crew was tired and needed to rest.  (Maybe call in another crew?)  So, she had to go to the ticket counter where there was an enormous line.  She stood in line for 4 hours!  Hear that, 4 hours!  And no one cared or once apologized.  Get this, during that time, one of the 2 agents left for a break.  When the agent returned, a person started applauding, which was followed by other applauding.  Know what happened?  The agent told them to settle down or she was going to call the police!  Someone said that they were just happy that there would be 2 lines and were clapping, and she threatened the crowd again!  Is this a foreign country?!  Are we still in the USA?!\nWell, 4 hours later, my girlfriend made it to the front of the line.  They wanted to put her on a flight the next day which would get her there at night, she would only have one day there and then have to return.  They offered her a credit.  She planned this vacation for months.  It cost her a lot.  She chose to take a flight out tonight, and risk one of the kids being on standby at their connection in Denver.  The agent said that chances are good that he'll get on.  If not, they will all be sleeping at the airport.  \nI feel so bad.\nPlease never fly United!