It's not hard to see why they named it "Bizzarria":
The Bizzarria Story (Home Citrus Growers)
I've seen a number chimeral citrus specimens before, but I've never seen the Bizzarria before. Apparently it's a graft hybrid of a sour orange and a citron. (Another much less spectacular citrus graft hybrid, Citrus neo-aurantium, can be seen here.).
This reminds me a little bit of the account of the "Sweet and Sour" apple in Apples of New York. Described as a probable graft hybrid, this apple had ridged fruit, with the ribs green and the space in between yellow. When eaten, the flesh in the green areas is tart and acidic, while that beneath the yellow skin is sweet and sub-acid.
Update: The more I poke around, the more I realize that the Home Citrus Growers website is pretty nifty as a whole. I'll add a link in the sidebar, too.