In Pictures: Apple vs. The World - Apple’s definit...
Apple v. NYC
In 2008, Apple filed a trademark opposition in regards to New York City's GreeNYC campaign logo, saying it too closely resembled Apple's. Funny enough, the logo in question also seems to house an infinite loop symbol. A few months later, NYC changed its logo by removing the leaf from the logo, and the logo was granted a trademark in late 2011.
In Pictures: Apple vs. The World - Apple’s definitive legal battles