What makes a good play party?

There's got to be a lot of varied opinion on this and I'd like to hear it.  I was at a party a few weekends ago that I fully expected to enjoy - frankly it seemed right out of a fantasy - enormous house, five rooms in an upstairs area designated as play areas, a great room suitable for dancing, a private yard and large deck with a clothing optional pool, a lot of people I knew or recognized, two friends on hand willing to play, good food, etc.  But I was extemely uncomfortable.  Surveying my friends all I got was "the vibe" was wrong.  Someone blamed the feng shui.  I thought the whole place was much too brightly lit and also seemed bachelor-pad grungy.  We didn't stay long.  What makes a play party work for you?