I've contributed with some articles. I'm rather disapointed, though. For example, I've rewriten the article on Lebesgue integration in the English wikipedia, since I find that the article explained the tenichal difficulties of Riemman integral, but it does not define the notion of Lebesgue integral (perhaps I had to tell you that I'm a mathematician, I work at the mathematics department of Buenos Aires University, Argentina).
After that, looking at the history of the page, I find that some rather old previous versions where much better, but they had been deleted since a user consider them "too advanced". Needless to say, Lebesgue integration is indeed an advanced topic in mathematics, so that any article on this subject is necesarilly advanced (or does not covered the topic).
So fix it. Revert it to the previous version, and argue your case on the talk page.
Another possibility would be to create an article for the general public as well as one with technical details etc., similar to [[M-theory]] and [[M-theory simplified]].