The story behind Perform This Way is also great:

In April 2011, Yankovic reported that Lady Gaga refused him permission to release "Perform This Way", which he had hoped to use as the lead single for his upcoming album. Yankovic had originally sent the request to parody the song to Gaga's manager, who responded that they would need to see his lyrics to make an assessment. Yankovic was touring in Australia at the time, and hastily created the lyrics for approval.[7] Yankovic further stated that Gaga's management insisted on reviewing a recorded version of the song, and he had cut a family vacation short to turn the recorded version around.[7] Ultimately, he was told that she refused to allow the parody.[8] Yankovic had considered the song key to his Alpocalypse album, but due to the rejection, he had begun the process to postpone its release until he could record a new song to take the place of "Perform This Way".[9]

Following the refusal, he released his parody online on April 20, 2011, and encouraged donations to the Human Rights Campaign. Yankovic was initially fearful of parodying Gaga's song, considering it "an important gay-rights anthem", but had hit upon making the parody about Gaga's fashion, and tying in the sales of the song and video to charity as an act of "good karma" due to the human rights message of the original song.[6][7]

Shortly after its upload to YouTube, word about the song spread among Yankovic's fans, primarily along Twitter, according to Yankovic,[9] and the video had received over 2 million views.[7] The word spread to Lady Gaga and her staff, and eventually it was discovered she herself had not yet heard the song and the refusal had come from Gaga's manager without her input.[10][11] As Lady Gaga is "a huge Weird Al fan",[12] she subsequently gave Yankovic the green light to include the song on his upcoming album and said she loved the parody.[13][14] Lady Gaga later considered being parodied by Yankovic as a "rite of passage" for her musical career and considered the song "very empowering".[15] Within a day of receiving permission to use the parody, Yankovic had reaffirmed the song's inclusion on Alpocalypse and was able to set the day of release for the album; Yankovic claimed that "Twitter saved my album".[9] Regardless of Gaga's permission, Yankovic will still contribute sales of the song to charity.[9]

Meanwhile Chamillionaire loved the parody of his "Ridin" (White & nerdy) so much he put it on his MySpace page and thanked Weird Al when he won a Grammy.

Also, Lady Gaga had no idea she was getting a Weird Al parody because her manager didn't communicate with her and was a dick to Al.

As I understand it, lots of musicians consider it an honor to have Weird Al approach them for a parody. He's respectful, appreciates creativity, and up front about everything he does. IIRC Lady Gaga was thrilled when approached. And the man is seriously talented; he can reproduce songs by ear, which is incredible, and if I believe me actually wrote The Saga Begins before the movie was actually in theaters, based entirely off of trailers and stuff. Which that's true that's fucking incredible.