"Once Upon a Time in Springfield" is the tenth episode of "The Simpsons"' twenty-first season.
 It originally aired on the Fox network in the United States on January 10, 2010.
 It was promoted as the 450th episode of the series, but is actually the 451st, and aired alongside "The Simpsons 20th Anniversary Special – In 3-D!
 On Ice!
".
 The episode is dedicated to Eartha Kitt, who died December 25, 2008, over one year before the episode first aired.
"Judge Me Tender" is the twenty-third episode and season finale of "The Simpsons'" twenty-first season.
 The 464th episode of the series overall, it originally aired on the Fox network in the United States on May 23, 2010.
 In the episode, Moe discovers his talent for judging in competitions and is invited to appear on the show "American Idol".
 Meanwhile, Homer drives Marge crazy when he starts spending too much time at home, and Lisa tries to comfort Santa's Little Helper.
"The Greatest Story Ever D'ohed" is the sixteenth episode of "The Simpsons"<nowiki>'</nowiki> twenty-first season and the 457th episode overall.
 It originally aired on the Fox network in the United States on March 28, 2010 (Palm Sunday and the eve of Passover).
 In this episode, the Simpsons vacation in Jerusalem with Ned Flanders, but Homer does not appreciate the city's religious importance—until he gets lost in the desert, and in a severe state of dehydration, believes himself to be the Messiah.
Mental (typographically stylized MƎNTAL:) is a television series produced by Fox's subsidiary Fox Telecolombia, which aired in the summer and fall of 2009 on FOX international channels for Latin America, Europe and Asia, starring Chris Vance and Annabella Sciorra.
 "Mental" was executive-produced by Deborah Joy LeVine – creator of the successful drama series "" and the Lifetime series "The Division", and executive producer of "Any Day Now", "Dawson's Creek" and the CBS series "Early Edition" – and her brother and writing/producing partner, Dan LeVine.
 Following its U.S. debut, it aired in 35 additional countries.
 Fox Latin America aired the first episode as a "Worldwide Premiere" on June 2, 2009.
 Fox aired the pilot episode on May 26, 2009 for the American market.
 Fox TV Studios ordered 13 episodes.
 It began production on June 2, 2008 at the Fox Telecolombia production facilities in Bogotá.
"My Big Fat Geek Wedding" is the 17th episode of "The Simpsons"<nowiki>'</nowiki> fifteenth season.
 It first aired on the Fox network in the United States on April 18, 2004.
 The episode was originally planned to air on April 4, 2004, but due to the voice actors going on strike, Fox aired a rerun instead.
"Moe Letter Blues" is the twenty-first episode of "The Simpsons"<nowiki>'</nowiki> twenty-first season.
 It originally aired on the Fox network in the United States on May 9, 2010.
 In this episode, Homer, Reverend Lovejoy, and Apu Nahasapeemapetilon receive a letter from Moe stating that he will steal one of their wives.
 The three get together and try to remember intimate moments between Moe and their wives.
"Postcards from the Wedge" is the fourteenth episode of "The Simpsons"<nowiki>'</nowiki> twenty-first season.
 It originally aired on the Fox network in the United States on March 14, 2010.
 In the episode, Homer and Marge once again try to discipline Bart after Mrs. Krabappel tells them that Bart has not been doing his homework, but Bart has a plan to manipulate Homer's strictness and Marge's sympathetic ear, which backfires when Homer and Marge see through the plan and decide to ignore Bart.
 These themes had been seeded in the previous season (e.g. "Double, Double, Boy in Trouble", and "The Good, the Sad, and the Drugly"), would culminate in the show's first ever true grounding, and the first to stand for the rest of the episode.
 It would also be the last episode to feature a grounding, until "The Marge-ian Chronicles" in Season 27, six years later (also written by Brian Kelley).
"Bart to the Future" is the seventeenth episode of the eleventh season of the American animated television sitcom "The Simpsons".
 It originally aired on the Fox network in the United States on March 19, 2000.
 In the episode, after their picnic in the park is cut short due to a mosquito infestation, the Simpsons stop by at an Indian casino.
 There, Bart is prevented from entering because of his age.
 He manages to sneak in but is caught by the guards and sent to the casino manager's office.
 The Native American manager shows Bart a vision of his future as a washed-up, wannabe rock musician living with Ralph Wiggum, while Lisa has become the President of the United States and tries to get the country out of financial trouble.
 "Bart to the Future" was the second episode of "The Simpsons" after "Lisa's Wedding" to be set in the future.
"The Simpsons"' twenty-first season aired on Fox from September 27, 2009 to May 23, 2010.
 It was the first of two seasons that the show was renewed for by Fox, and also the first season of the show to air entirely in high definition.
"American History X-cellent" is the seventeenth episode of "The Simpsons"<nowiki>'</nowiki> twenty-first season and 458th overall.
 It originally aired on the Fox network in the United States on April 11, 2010.
 In this episode, Mr. Burns is arrested for possessing stolen art and Smithers is chosen to run the nuclear plant—only to turn into a misanthropic slave driver when his subordinates begin taking advantage of his kindness.

Question: When does the seventeenth episode of "The Simpsons"' twenty-first season which was renewed for by Fox aired?
Answer: April 11, 2010