WordPress continues to amaze me with it’s ability to respond to nearly every feature request. While working on a client site this week, the requirement to block a category from the main blog feed was requested. A minute or two with Google turned up the Advanced Category Excluder plugin which gives you this feature and the ability to show your modified “recent posts” in the sidebar.
But the client also wanted to have a single category feed show up on the sidebar which proved to be a slightly more difficult problem to solve. But I was able to find another plugin, Archives for a category, which adds the ability to filter on specific categories in your WordPress archives code. Add the handy Executable PHP widget and then put in the code to display your category posts. In this case it looked like this:
But you can do the same thing for multiple categories like this:
Let me know if I can help you with your WordPress site.