Perhaps a bit more info on the "about us" section.
As far as functionality goes, it seems to all work.
As for design, it could probably use some improvement.
Your home page is a little cramped looking.
Try and keep a consistent header across the website.
Edit: May I suggest you try and use that extra white space on the sides? If you were to expand your "main" div, you could fit more content spacing, possibly reducing the cramped look. Also, you might be able to fit your navbar on one line, instead of 2. (This can also be achieved by changing the padding in the li class "noncurrent-page" from "padding: 0 10px" to 0 5px.)
You could also add a footer for extreme awesomeness.
Oh, and a technical question-
Why are you using dropbox to store a html file, then have your .tk domain just display one large frame?