My hair is always the exact same way. What I usually do is do a little braid on the side then bobby pin it to give a touch of something. Or I usually tuck a little piece from the front of my hair behind my ear to give it something. Or just curl or crimp it!
You're so lucky to have straight hair! I can assure you it looks good down. If you don't have one already, make it a side part. It changes your entire look! And if you think your hair is too flat or something, tease a little underneath! :)