How to get air from a winodw without a light leak?

I'm trying to figure out how to cover the window in my room without leaking light (or allowing snooping eyes to look in) What do you guys think would be good for this? My friend said drapes would be good because they wouldn't look suspicious, but I think they could leak light along the sides.

There is a fabric called blackout fabric, you get it at (of course) fabric stores. No light will penetrate it and you can make something to fit your situation.

build a box arond it with a duct that runs to ur room... bathroom fan optional but reomended

dryer duct home depot