• TCM has classic war/military movies all day and night.
• At 6am, USA has an NCIS marathon.
• At 8, A&E has a marathon of City Confidential episodes.
• History Channel has a MonsterQuest marathon at 8.
• Sci-Fi has a Star Trek: Enterprise marathon at 8.
• Also at 8: TV One has a Day Break marathon.
• At 9, BBC America has a Monty Python's Flying Circus marathon.
• FX has a That 70s Show marathon starting at 9.
• GSN has a Match Game marathon at 9.
• Spike has a CSI marathon starting at 9.
• At 10, TNT has a Law and Order marathon.
• At 11, G4 has a Cops marathon.
• Lifetime has a bunch of "sex" movies starting at 11.
• At noon, GSN will have a special GSN Live from Iraq, featuring ex-game show contestants who are stationed there.
• There's a Top Chef marathon on Bravo starting at 2:30.
• At 4, Discovery has a Deadliest Catch marathon.

(Thanks to Interesting Pile)