A manhole exploded in the Bronx last night. Luckily, no one was injured, though people were left without electricity and had to be evacuated because the carbon monoxide levels went up. Gothamist wonders if this is the start of the manhole season. Have you heard of any incidents recently?
How Stuff Works explains how manholes explode. Gothamist on exploding manholes and manhole tattoos. New York magazine on manholia (fear of manholes) and DC had a spate of manhole incidents - here's the Washington Post's manhole section.