I started with one not-too-fresh egg (last one in the carton), plopped it in a pot of cold water, and set it on the stove to boil while the tea was steeping. Went into the bedroom to read the SDMB (plug!). After a couple of minutes, I heard a loud “crack” from the kitchen. The water was boiling, and the blunt end of the eggshell had blown off. It was in three pieces: one loose on the bottom of the pot, one still attached to the egg by a bit of membrane, and the third, a half-inch triangle, on the stovetop a full foot from the pot. Exploding egg!
The egg looked, smelled, and tasted perfectly normal.