Today marks the 50th anniversary of the Beatles' landing on U.S. soil for the first time. It's a pretty big deal, and an event that's being celebrated all over the place -- from magazine covers and online feature stories to record-store shelves and television.

CBS has been marking the anniversary all week. It culminates in a special Sunday night that includes contemporary artists covering the five songs the Beatles played during their Sullivan debut. Every night this week, 'Late Night With David Letterman' has also celebrated the music of the group with guests playing some of their favorite Fab songs.

On Monday, Broken Bells -- which features Shins frontman James Mercer and producer Danger Mouse, the mastermind behind 'The Grey Album' mash-up between the Beatles' White Album and Jay-Z's 'The Black Album' -- covered 'And I Love Her' with some 'I Am the Walrus' thrown in for good measure. Here'e a clip:

Sting also showed up this week to sing 'Drive My Car,' and Lenny Kravitz checked in with 'Get Back.' But by far the weirdest performance to hit the show was last night's collaboration between the Flaming Lips and Sean Lennon, the son of the late John Lennon. They played 'Lucy in the Sky With Diamonds,' which was originally on the Beatles' landmark 'Sgt. Pepper's Lonely Hearts Club Band' and was reportedly based on a drawing Lennon's other son, Julian, made when he was little. But we all know it's really about drugs, right?

Which made it a fitting choice for a Lips cover. Bringing their usual mix of glitter, bombast and WTF-is-going-here?, the band overhauled the Beatles classic with tripped-out wonder . . . and with frontman Wayne Coyne dressed up like a psychedelic Christmas tree. Plus, Lennon was sporting his dad's 1969 look. You can watch their performance below.

There's a reason for all of CBS' enthusiasm. On Feb. 9, 1964, the band played 'The Ed Sullivan Show' for the first time, effectively kicking off Beatlemania in America. Sullivan's weekly program was broadcast on the network, and the very same studio is used as Letterman's home base these days. And rumor has it, the surviving Beatles -- Paul McCartney and Ringo Starr -- will be on tonight's show.

UPDATE: The clip is no longer available.

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