Now house party is a pretty generic term that can mean anything from parents needing a place to socialize that's kid-friendly to formal cocktail soiree to house-trashing, cops coming crazy town. For the purposes of this post I'm considering it something in between: adult but not out, with hip music just loud enough that you can hear a conversation but maybe jam out a little too.
I personally think a house party is the perfect chance to dress up some cute shorts!!! I love the idea of rocking leopard print ones with a tight hot pink top and throwing a oversized, chunky knit sweater on top to balance it all out. Since you should be able to find a place to sit if needed, pull out your tall, uncomfortable shoes that make your legs look super long! And be sure to wear a bright, stand out coat - easy to find when there are 30 thrown on the guest bed!
See my previous what to wear posts - NYE at a Posh Club and NYE at a Hipster Bar!