Possibly this Dior number, complete with wackadoo hat:
But only if I was feeling in a Helena-Bonham-Carter-meets-Dita-von-Teese-for-tea kind of mood. If I wanted to wear something more Oscar-appropriate, it would probably be this dress that Anne Hathaway wore during one of her many costume changes (although I would DEFinitely not wear my hair in this cracked-out bowl shape that the blonde model is wearing):