The 3.5 kernel has been released

Linus has announced the release of the 3.5 kernel.
Headline features in 3.5 include
the CoDel queue management algorithm (a
piece of the solution to the bufferbloat problem),
the seccomp filters sandboxing mechanism,
autosleep (an alternative to Android's
opportunistic suspend mechanism),
the uprobes user-space probe subsystem,
the contiguous memory allocator,
the new kcmp() system call,
metadata checksumming in the ext4
and a lot more. See the KernelNewbies 3.5 page
for more information, though it appears to be still under construction
as of this writing.