The G-20 protests have generated a lot of geeky news. In additional to the usual tear gas grenades and stun grenades, this year's G-20 protest marked the first public use by the government of a 150 DB sound cannon against civilian protesters. The result was a call for a DIY HERF gun that protesters could use to disable the sound cannons. Next, the FBI arrested Elliot Madison for using twitter to describe police movements during the protests. (the EFF has just obtained the legal documents for the Madison case) Now, we've heard that the CMU Machine Learning Lab has put on their own G-20 protest, demanding attention be given to important AI and robotics issues with such punchy slogans as "free variables", "support vector machines", "repeal power laws", "Baysians against discrimination", "end duality gap", "ban genetic algorithms", and of course, "Map reduce, map reuse, map recycle". Arthur Gretton shot some nice photos of the protest, one of which is included above.