Sorry to post again already, but I just found
this article by Powderfinger's drummer, Jon Coghill (usually known as Cogsy) which has a whole paragraph about Chris's drumming:
Chris Cester of Jet is one drummer that doesn't hold back when it comes to pulling a face or two and I don't think he even knows he does it. Like many fine drummers, Chris can pull a few monkey faces while laying into a sublime rock groove, but it's when he rolls on his snare or attacks a big accent we get a visual of his innate urges. Chris's mouth will stretch wide open and he'll appear to be yelling directly at his tiny four piece Ludwig kit. A whole song can be littered with up to a hundred of these little eruptions and you may suspect that he is the love-child of Keith Moon and Animal of the Muppets. While Cester's pulsing backbeat propels his band mates, his facial expressions take on a life of his own, only to be released momentarily between songs.
I'm glad I'm not the only one who thinks Chris has a bit of a monkey face sometimes. Then again, Chris himself once said something like "I just wandered out of the jungle in a loincloth and ordered a gin and tonic."