Also, I just wanted to point out that my internship was my project (it wasn't a response to an open opportunity). So if you don't see any posted projects, you should definitely come up with what *you* want to do and email some potential hosts. I emailed a scientist at the Smithsonian, told her my idea, and asked if she would be willing to be my "host", even though my research isn't directly related to what she does. Good luck!