Ubuntu is known for having the funkiest release code names around. Version 10.04 (to be released in April, 2010) will be named "Lucid Lynx", points out the Ubuntu wiki.
Lucid Lynx will be a LTS release (supported for 5 years) and will ship with Gnome 3 as a default.
In case you don't know, the 2 words in the Ubuntu cod names follow this pattern: "Adjective Animal", so that's where Intrepid Ibex, Jaunty Jackalope, Karmic Koala and now Lucid Lynx came from (notice that the 2 words always start with the same letter).
On the same Ubuntu wiki page, there are already sugestions for future versions, some of which are very funny. For instance, here are some suggestions for Ubuntu 10.10: Marauding Macaque, Majestic Manatee, Merry Meerkat, Modest Mouse, Maudlin Manatee, Magnificent Mara, Mysterious Mockingbird, Mutinous Mouse. And that's just for 10.10; there are suggestions for even later Ubuntu versions.
[image via wikipedia]