Eugeni Dodonov has shared on the mailing list that Mandriva 2010.2 (the stable-update successor to Mandriva 2010.1 from this summer) is set to be released on 22 December, just in time for Christmas. Mandriva 2010.2 carries bug-fixes, updated packages, and a refreshed desktop theme.
At the same time, the developers left working on Mandriva are working towards their first 2011 release. Mandriva 2011 is set to go into an alpha state by the end of January while the final release is expected to come on 30 May. There will be two betas in February and March and the release candidate coming in late April. There is now this Mandriva Wiki page concerning the planned 2011 release.
A release late in May of Mandriva 2011 is putting it a month after the Ubuntu 11.04 release and days following the Fedora 15 availability. While technical details and new features for Mandriva 2011 have yet to be announced, it's anticipated this next major release will ship with the Linux 2.6.37 or 2.6.38 (hopefully) kernel, X.Org Server 1.9 (potentially 1.10), GNOME 3.0, and GCC 4.5, among other new Linux packages.
Last but not least, Mandriva SA has decided going into 2011 they will focus upon just releasing Mandriva once per year (rather than twice or more). This is being done to conserve resources, of course, and to ensure their annual releases are now greater by providing additional time for testing and validation.