Sweet and tasty heirlooms - Uchiki Kuri (just about old enough to be called 'heirloom') and Buttercup. A very sweet acorn squash (recently bred but delicious) is Tuffy.

Bella trix, Galina is on the right track - "Kabocha" squashes are usually C. maxima, buttercup type. Generally, the blossom end does not protrude. Besides the Asian kabochas, the gray Austalian squash "Queensland Blue" & many of the buttercups have similar quality. Sand Hill Preservation & Baker Creek are both good sources for kabocha & similar.

Im looking to find where they harvest this Kabocha Squash at Im in California do you know of where I can find this squash or who grows them ????

The biggest selection of hybrid (not heirloom) Kabocha squashes is stocked by Kitawaza seeds:
http://www.kitazawaseed.com/seeds_winter_squash.html

similarly Evergreen
http://www.evergreenseeds.com/

Synergy seeds stock a heirloom Kabocha, open pollinated, not hybrid
http://www.redwoods.quik.com/webteck/george/vines.html

Also Kokopelli seeds stock open pollinated Kabocha, if you can get seeds from France.

I'm about to order some open pollinated Kabocha. Check it out! I'll be growing these in a my three sisters and a foreigner(the Kabocha)garden.

Blue Kuri
Cucurbita maxima
A traditional open pollinated Japanese kabocha squash that has globe-shaped fruit with blue-green skin. The flesh is thick, yellow and very sweet. Fruit matures to 2-3 lbs and is 6-8" in diameter. The plant has a vine growth habit.
http://www.kitazawaseed.com/seed_043-187.html