photography portfolio

my last assignment of the year is to create a portfolio...
one "theme" and then three smaller sub-themes that relate to the larger theme and to each other but in a good way, not a boring one.

so...basically...i have no idea what to do.
i was thinking about doing something involving crew, because that's the easiest place for me to get pictures - but i really want to do portraits. also, i just got a new camera (nikon d300 *DROOOOOOOOL*) and i don't know if i want to risk hurting it there. things...get broken, at the boathouse.

my ideas/first set of pictures are due friday and i'm lightweight freaking out on what to do...
any ideas?

Maybe you could do cultures? Like, your main theme could be America and then under that, the different races living in America. It'd be pretty cool, just that it might involve a bit a running up and down to different areas and stuff.

Idk. Just a thought.