Yesterday was a ...

Good Day for sewage, as the city of Yokohama in Japan announced the results of an experiment in using the "digestive gases" formed by the sludge resulting from the purification of domestic sewage as a source of energy. The trial has shown that the sewage from one city can provide enough power for 100 average households.

Bad Day for obesity, as Ronaldo Bertolotti, a 320lb Brazilian, initiated proceedings against a dentist who refused to treat him because he was too fat. "He said he would not treat me because his chair might break," he alleges. The dentist, however, says his only concern was for his patient's safety: "I didn't want to treat him because I was worried that if the chair broke, he might have hurt himself."

Stable Day for sandcastles, as the science journal Nature reported that "interstitial liquids can alter many aspects of pattern formation, self- organisation and segregation in granular material, potentially leading to new physical phenomena not encountered in dry matter". This newly discovered property is known as "the sandcastle effect" and explains how castles made with wet sand can retain their shape even after the sun has almost totally dried them out.