All day, and for the rest of the month and beyond, The Simpsons will be on FXX any time you tune in there. But I highly recommend making a point to catch or record the network late tonight, at 1:30 a.m. ET, when FXX presents “Who Shot Mr. Burns?,” the brilliantly funny two-parter that ended Season 6 with a cliffhanger, and opened Season 7 with a very satisfying conclusion back in 1995. The two-part mystery riffed on everything from Dallas to Twin Peaks, including a dream sequence in which Chief Wiggum is fed cryptic clues by a backwards-talking Lisa in a weird red room.