Giggs had threatened to stay in bed on Friday - his 40th birthday - for fear of the pranks that might be played on him at the Aon Training Complex.
And Moyes confirmed the Welshman had indeed been the centre of attention.
"There were one or two surprises for him in the dressing room," said Moyes.
"One was a coach's watch - I think they are trying to push him out of the door."
Given his performance against Bayer Leverkusen in midweek, speculation has already turned to whether Giggs will be offered a contract extension when his current deal ends at the end of the season.
Moyes does not feel it is the right time to discuss such matters.
"When you get to this age it is always a late decision and you wait until the end of the season," he said.
"It is based on how you feel, how you have done over the year and what your body is telling you."
But there is no doubt, when Giggs eventually decides it is time to end his career, it will be remembered as one of the finest there has ever been.
"He's undoubtedly at the top because of his longevity and the time that he has played for just one club, the amount of games he has played in Europe and in the Premier League," said Moyes.
"Every season, you can look at Ryan Giggs moments. To be playing so well at his age is terrific and a great example to young players about how you should dedicate yourself throughout your career.
"It also tells players who get into their early to mid-30s and think things are coming to an end that if they really look after themselves and train well, they can go on for a lot longer."