Agree that the header is too tall, especially since it's static.
I also think you've used too many different fonts which leaves the page looking a bit cluttered and lacking cohesion. It would be better to reduce the number of fonts and possibly make better use of font families to tie all the content together. You've mixed serif and sans-serif fonts together and it makes the page look disjointed. I count six different font families on the main page alone and no font size consistency.
There's too little whitespace on the text-dense pages (like "About") and you could stand to have a bit more vertical whitespace around the headers and definitely more margin space on the sides (within the white container, not on the page as a whole).
Other pages, though, are not dense enough. Contrast the density of the About page compared to the density of the "Members" page. I realize that the content itself makes that a challenge, but it is a problem. Perhaps adding small bio pic photos to the members page, or expanding the amount of detail shown for each person listed could help add some weight to that page.