I have found myself having the same problem sometimes too. After writing 100 plus blog posts or articles, you start to run out of ideas. One thing I like to do is visit the free keyword suggestion tool via Word Tracker. I am unsure of the site address right now, but it can easily be found with a standard internet search.
I then take a few words or phrases from my blog. For example, one of the sites I have is preschool themed with crafts, activities, worksheets, and so forth. So I usually try something like "preschool crafts" in the keyword suggestion tool. I'll get a bunch of different phrases people search with. Some are more detailed than others.
For example, once I think I found preschool crafts with leaves. That phrase alone gave me a worth week of content. I sat down and branched off that simple phrase.
You might want to try this approach.