Flat Athletics Hairstyle Help?

I want to change how I do my hair. I'm in athletics first hour for school and so I only get so many minutes to get ready. I also sweat and put my hair up in a ponytail for about an hour also, so curling before school is not an option. I want to quit straightening it for a little while [or do it minimally] because I do it every day and that's bad. I want a messy style, but not really messy. I saw Jillian's from the Biggest Loser last night, and I liked hers. I've got medium to sorta long hair. How can I do this? Any ideas?