Blue Screen in Kdenlive (Chris Pirillo community challenge)

This is a clip that I made for the Chris Pirillo Community Challenge 5

http://www.youtube.com/watch?v=M38Qdf9JFM4

I used the blue screen effect in combination with the composition transition to pull this off.

What real color of background did you use? What light? How many lamps, which type (resistance, halogen, warmness) and power?
Has anybody another examples of using this effect?
How animated tie was implemented?