"Activities."

I've just become an official candidate for the Naval Academy, and in the package they gave me of stuff to fill out was an "Activities Record". I'm still afraid to turn it in because it will look so shrimpy.
It wants me to submit how many extra-curricular activities I've pursued. Any suggestions on how to beef it up before the submission deadline this fall?
I've spoken with both the Red Cross and Habitats For Humanity about volunteer work for the summer, which will look a little impressive. However, I've never been in things like boy scouts, student government, and hardly any sports. Keyword: Homeschooled.
Any input?