Prom ideas for long hair

My senior prom isn`t for another 2 months or so- but I`m trying to get a start on my hair now. I`d like to do it myself (I have people that will help me, of course) to save on expenses.
I have a LOT of medium-long dark hair that is both really thick (it gets incredibly frizzy if left on it`s own) and really heavy (it won`t hold curl,even with gel, for more than 3 hours if I sleep in curlers and leave them in the next day).
Last year I had an upside-down french braid then curled all the ends and pinned the curl to my head. to finish it off I put in a thin headband that matched my dress. This year I`d like to do something different. Any ideas?
My dress is long with a tight bodice and a slightly pouffy skirt. My hair falls just past the back line. It`s dark silver that turns purple in the light with black roses all over.
Any suggestions would be appreciated.