If you're having a block this weekend, or none of the request appeal to you, consider writing about medical advances in technology, drugs, or procedures. Cancer treatments, discoveries in Alzheimer's, Parkinson's, or MS research, or new information for diabetes sufferers or the obese are all fair game.
After you've identified your topic and scientific studies that explain these medical advances, use search engines to try and find the original studies - or, in the very least, copies of their abstracts. This will guarantee that the information you have is correct and lend your article more authority. Don't forget to reference your sources at the end of the piece.
Basic starting points for further investigation include BBC's health section or Slate's Human Nature column.