Some of Christopher Brookmyre's books can be good. I'd go with A Big Boy did it and Ran Away. The opening of absurdist bank robbers, and the references to Waiting for Godot and the Sensational Alex Harvey Band throughout, did it for me.
I'm not a huge reader of 'humorous' novels, though. I tend to prefer humour dotted through a 'serious' book. So if it's amusement I'm looking for, it's often with short stories. I've been a fan of Saki for ages and Sredni Vashtar is my standard for dark humour in a short story.
There is one other book, although it's poetry, and originally intended for kids - Old Possum's Book of Practical Cats, by TS Eliot. Guaranteed to lighten my day.