I once played mortal combat for like, the whole day and when I tried to get to sleep I would see game footage or something.
When I was younger, I looked at a heap of L4D videos before I went to sleep and when I closed my eyes I would see the blue outlines of items and other survivours.
I recently spent 22 hours in a car going to and from brisbane and when I layed in bed I felt the sway of the car. Could not. Go to. Sleep.