On Australian television, especially the commercial stations (rather than the 2 government run stations we have broadcasted nation-wide) there is an overwhelming load of American "comedies", which, now you mention it, do seem to be based on the "dumb is funny" idea. I tend to avoid these shows. But every now and then an intelligently funny American comedy show comes out and it is worth watching, e.g. Just Shoot Me, or lately I have discovered the cartoon called Daria (an offshoot character from Beavis & Butthead).
Generally, if it is billed as an American comedy or especially an American sit-com I find it not even worth looking at. But if it is British it tends to be worth checking out because their humour tends to be more subtle. Australian comedies are a mixed bag. Some good, some pretty silly, but the satirical stuff is up there with the best of the world's humour.
I didn't want to prolong the agony in the Aussies ban American bands thread (please, let's let sleeping dogs lie here, too) but there is a show on the government/nation-wide channel (ABC) called The Games which is written mostly by John Clark, and features him as one of the main characters. It is a satirical portrayal of the Olympic Games organising committee and the politics and the sheer stupidity of it all. It came out just after it was announced that Sydney would get the Games, and it is being re-run now. It's hard to believe in the Olympics process after watching that show, even if you were naive enough to believe in government-run bureaucratic organisations before that.
John Clark has the driest sense of humour of any comedian/satirist I have ever seen. He is clever and insightful, scathingly funny. I'd hate to be the butt of one of his tirades, not because he is nasty, but because he is so accurate - like looking into the clearest mirror in the world - no illusions/delusions, no secrets, just a clear picture of reality.
That's humour, for me. Not schoolboy jokes and airhead characters.
Just my AU$0.02c worth.