Check out this animated version of a runway incursion at Boston's Logan airport, between Aer Lingus and USAir. The incident actually happened on June 9th, 2005. Scary stuff.
Both aircraft were under control of the Boston Air Traffic Control Tower; the local control west (LCW) controller was responsible for EIN132 and the local control east (LCE) controller was responsible for USA1170. At 2339:10, LCW cleared EIN132 for takeoff from runway 15R. Five seconds later, forgetting that he had released the runway to allow EIN 132 to depart, LCE cleared USA1170 for departure from runway 9. The first officer on USA1170 saw EIN102 and pushed the control column forward to prevent the captain from taking off. Once EIN132 had passed through the intersection, USA1170 became airborne.:eek: