First, there's Brian Switek's insightful piece from the Smithsonian On-Line Magazine:
Everything You Wanted to Know About Dinosaur Sex
This piece has some wonderful stuff in it, good scientific premises, and raises some interesting questions about the subject. It also demonstrates how much we know - and don't know - about dinosaurs and their sexual means, but goes to show that one can take things seriously on the subject. I actually learned quite a bit of interesting stuff that I didn't know from this article.
Then we have Brian Palmer's The Explainer piece on the same subject.
How Did Dinosaurs Have Sex?
Not so much serious, but definitely providing a slightly different view of the subject. Still, both pieces are insightful in their own ways, and make for interesting, educational, and at times humourous reading.