For those that haven no idea what a Narwhal is, it follows earlier Ubuntu code-names of being an animal, and the Narwhal is a medium-sized toothed whale that lives in the Arctic. They're a unique animal and you can find out more about them if you wish over at Wikipedia. The Natty Narwhal succeeds the Maverick Meerkat, Lucid Lynx, Karmic Koala, Jaunty Jackalope, Intrepid Ibex, Hardy Heron, Gutsy Gibbon, Feisty Fawn, Edgy Eft, Dapper Drake, Breezy Badger, Hoary Hedgehog, and Warty Warthog. The Natty Narwhal may not be the best Ubuntu code-name to date, but at least it's better than Fytnargin, which is what Fedora 14 was almost called.
In Mark's Natty Narwhal blog post, he shares that with Ubuntu 11.04 they will continue to improve the sleekness and style of Ubuntu Linux, Ubuntu Narwhal will take special interest in "making the most of the amazing capabilities of modern graphics hardware, both for outer beauty and for inner efficiency", and Ubuntu 11.04 will continue to have a great focus on ARM support and other low-power systems.
Ubuntu 10.10 "Maverick Meerkat" is due for release this October while Ubuntu 11.04 "Natty Narwhal" is set to be christened in April of 2011.