There are a number of ways that you can get fresh ideas for articles. The Internet is the first place I will say to look for ideas for articles. Whatever your niche is, there is a place for you to find ideas for articles. You can go to forums in your niche and see what questions people are asking in your niche, and write an article that answers their questions. You can also go to the groups in google or yahoo in your niche and do the same thing. See what people are asking in these groups, or problems they are having. This is great feed for coming up with ideas to write articles.
Yahoo answers is another great place to get ideas to write articles as well.

To get other great ideas about writing articles, read this review on how to turn your articles into traffic.