Although various heady jams that would appear on In Rainbows trickled out several years prior, including "Arpeggi" and "House of Cards" in 2005, the first taste came with Thom Yorke's breathtaking solo acoustic encore "Big Ideas" on the last night of their 2003 tour supporting Hail to the Thief. Of course this stripped-down version later became "Nude" - and the fact that Radiohead can sit on songs this good for that long makes you wonder what's in the vault.
Radiohead - Big Ideas (Nude - acoustic live 12/4/03)
Thom Yorke - Reckoner (acoustic live on Johnathan Ross)
While we're on big ideas, LCD Soundsystem offers a new suburban treadmill motivator via the 21 soundtrack arriving 3/14, per usual James Murphy builds steam using only handclaps and a grain of salt.
LCD Soundsystem - Big Ideas