Any ideas for a loose/half updo for long wavy hair?

Im supposed to be going out tomorrow with some friends and my sister is tagging along too, she has long dark brown wavy hair and she always wears it down. Shes coming over tommorrow and im trying to find some stuff to suggest for her to dress up, but i have no experience in styling long hair (I never even did my hair when it was long -.-'). The tools i have are a medium hold hairspray, styling mousse, a styling gum,regular hairbrushes and a large round brush,blow dryer, bobby pins, clear plastic hair bands and some random hair peices. thanks in advance :)