Ok, so my schools homecoming is semi formal, and I hate to have to wear the general "Oh look I work in a office building" shirt and tie.

I was hoping to find something more Alternative to wear, I was already planning on wearing my combat boots, but can't think of what else to wear with them to make it technically semi-formal.

I would just follow what they say but wear unexpected colours.

Jeans, stylish slim fit shirt and bomber jacket.

Wear shorts that come just below the knee (but keep them classy) and a tailcoat with deep red lining :3
Oh, and a top hat.

Wear some nice outfit and then just throw a sports jacket over it.