Krav Maga (Hebrew for "contact combat") is an Israeli fighting system, devised in the 1940s by the late Imi Lichtenfeld. Adopted by numerous law enforcement agencies and militaries around the world in official and unofficial forms, it focuses on neutralizing threats as quickly and effectively as possible. To achieve this level of effectiveness, it borrows from numerous established marshal arts.
Brief Instructional Video
(Note that this is not an appropriate response when someone tries to surrender you in paintball...)
As previously stated, I have been looking for ways to spend my time in the near future, and will be trying Krav Maga next week. If anyone in the Ottawa area wishes to come out with me, please visit the Krav Maga Ottawa website and let me know.