Here's a riveting turn of events in the ongoing Spears-Federline custody saga that's all but certain to push the name Jamie Lynn to the tabloid sidelines for a minimum of two publishing cycles: The "Gimme More" singer's stubborn refusal to hand over her two children to K-Fed's custody led to a four-hour police showdown at her home tonight, requiring the presence of several squad cars, firetrucks, a helicopter and an ambulance—the last of which carted her off on a gurney to Cedars-Sinai Medical Center. (Footage courtesy of myfoxla.com, accompanied by running commentary from a cameraman whose gripes of having to "follow this frickin' thing to the hospital" suggest he may not have been entirely aware his audio was being broadcast throughout the internets.)

Authorities have now confirmed that Spears was "under the influence of an unknown substance" when they arrived, perhaps after the singer's sudden and utterly inconsistent interest in her children suggested she may have been experiencing the powerful, neglectful-mind-altering effects of a controlled intoxicant. Both children are reportedly now in K-Fed's care, the elder demanding to know "why mommy's eyes look like big, black M&M's, daddy?" More on this stunning development tomorrow, as Britney Spears-Police-Showdown -Custody-Disaster- Under-the-InfluenceGate (we promise to come up with a catchier title by then) continues...