Because Hearing HAL Sing Wasn't Strange Enough...
Bicycle Built For 2,000 is comprised of 2,088 voice recordings collected via Amazon's Mechanical Turk web service. Workers were prompted to listen to a short sound clip, then record themselves imitating what they heard.
The song "Daisy Bell," originally written by Harry Dacre in 1892, was made famous in 1962 by John Kelly, Max Mathews, and Carol Lockbaum as the first example of musical speech synthesis.
ps here's HAL singing.