This has to be the single best toy to come out of a cereal box.
The box contained 2x regular boxes of Coco Pops (which at this particular time were being called Choco Krispies) and each had its own toy lightsaber in. The best bit is this amazing R2D2 breakfast set - an R2D2 model which comes apart into 2 bowls, two spoons, a cereal container and two spoon holders. God bless Ebay! (£10)
I believe this was a Kelloggs promotion in Spain only, as I've never seen it in the UK and it was promoting the release of Star Wars Episode 3.