It doesn't happen often, and it is quite good for Randolph to do it. Dwight had more than half of his team's rebounds pretty recently (6 days ago) on Dec 31st. 22 of 41. On Dec 29 he had 21 rebounds of the team's 42. On Nov 31, he had 23 rebounds of the team's 43. On Nov 9th, he had 20 rebounds of the team's 40. Against NYK.
I called this. I noticed "wow, Randolph is only averaging 10.0 rebounds. He's gonna get on those boards tonight, to get that average a little higher...so that he'll have a double-double". Honestly, it seems to me like Randolph is a stats whore.