I started her hair similar to Boo's for Dr. Seuss Day. The idea to do this (or at least the top one) came to me last year, but she wouldn't let me do it then. This year she was all excited to be wacky. My girls have thin, fine hair. Sis has more than Boo, but still doesn't have a lot. My secret: cones. Since she doesn't have much hair I just rolled card-stock into the shape of a cone and stapled it together. If your daughter has lots of hair try using a Styrofoam cone (but be warned Styrofoam costs more than it looks like it should).
Make a part (I did mine zig-zag to add more wackiness) around in a circle on the top of her head. Insert cone in the middle and pull the hair up around it covering the cone. Put in an elastic at the top. I tried to put it on the tip of the cone, but it just slid off. At the top it doesn't matter so much, just get it as even and tightly secured as possible.
Part the rest of the hair in half. These cones are a little harder to put it. It is nice on the top cone that it can just sit on her head. On the two side cones I actually put in two elastics. One first at the end of the cone and a second over the cone and hair (near the end). Tie with some not matching ribbon.
Yes, I did use hair products. If I had more time (i.e. a little notice about spirit week) I would have tried to pick up some color spiking gel that we used in my son's hair for Dr. Seuss day. That stuff has some serious hold to it. I've only used it the once, but I may have to get more and investigate the possibilities. But, alas no hair color to be had (or purchased) so I used what we had at home: Garnier Fructis Style fiber gum putty and hairspray. It worked and was still standing strong when she came home from school!