It's Christmastime, and now that your grandmother and maiden aunt are on Twitter, choral flash mobs are the new big thing! Hundreds of people gathered "spontaneously" at malls in Orlando, Dallas, and Kansas City over the weekend to sing a rousing "Hallelujuah Chorus" en masse, much to the delight of the elderly and local news broadcasters the nation over. But when a similar gathering tried to happen up in Roseville last night -- following weeks of reminders by local church groups, choral groups, etc, on Twitter -- at the Westfield Galleria food court, way too many eager singers showed up, and suddenly the flash mob started to feel like an actual mob, and the mall had to be evacuated.

Said one participant, "The floor was bouncing a little too much. I heard a few people say it seemed like an earthquake," she said. Sadly, no singing happened, because the crowd got too huge too fast.

The mall only recently reopened after an October police standoff with a crazy dude who set fire to a Gamestop store, and subsequently caused a huge blaze that spread to other stores. Last night forced the mall to close again, but it's expected to reopen this morning, following a bit of structural inspection.

Maybe this will teach the olds that Twitter is not a game, and that flash mobs really aren't that fun? Or maybe the greater Sacramento area will propose outlawing flash mobs like San Francisco was thinking of doing.