• A major PG&E gas transmission line that serves San Francisco ruptured during a pressure test, "blowing a crater in an alfalfa field," south of Bakersfield. [KTVU]

• The "App gap" is a real problem facing children whose parents can't afford the pricey smartphone apps others use to get their kids to shut up, says the New York Times. [Gawker]

• Everybody wants to know about that part in Steve Jobs' biography where he wants to build an integrated TV set. [Bloomberg]

• Medical marijuana advocates are planning to protest Obama's visit today. [TheSnitch]

• An outbound N-Judah popped off the tracks at Duboce Park during yesterday's evening commute. No one was hurt, unless you count the pain of having to take a Judah shuttle home. [MuniDiaries] [SFEx]

• Leland Yee will be hanging out in the Lower Haight today. [Haighteration]