Our annual company party is next weekend. I haven't been to one since I started in 2007, so I decided I would go to this one. It is semi-formal. What exactly does that mean? I have a cute party dress, but the length is just above my knee. I will be wearing black opaqe (sp?) tights. Do you think that would be appropriate? And someone told me that means Dh has to wear a tie?

Sounds like you are on the right track. I would think Semi formal means a dress and at least a sports coat for Dh.