SexKon obviously but nah, just ask, you never know the level of dress up until you get there. You might be told its fine, and have a wicked suit that fits right in with the them, get all dressed up, gear u know wont interfear with the job and then you get there and everyone is wearing casual clothing with a simple bowtie round the neck. Then you just look like a twat. no real fault of your own just sucky circumstance. I always have with me formal attire (a shirt tie and dress pants) as well as a set of casual clothes because you never really know how an event will go down. Ive been to a couple where i have arrived very overdressed (elderly parties etc etc) and been glad to have the option. that being said, nothing worse than arriving under dressed and looking like the 'kid' from round the corner. If your going to dress up do it right or not all all, because you can always take stuff off, but if u arrive without enough ur screwed. I always say, dress to impress. And if your not impressed by yourself you probably havent done a good enough job