A fairly obvious name in a discussion of humour is P.G. Wodehouse. However, not everyone knows that he wrote a great deal of excellent comic poetry in addition to his novels and short stories. Here's a
link to one of his funniest poems, "Good Gnus". It's even funnier in context, as is explained by the person posting the poem in the thread I've linked to.
I love the parenthetical comments in the poem. And "a kopje or a cactus" is a definite LOL line for me (never thought I'd use this abbreviation but it seems appropriate).