Linux kernel 3.3 was released with Android code merge, improved Btrfs, and EFI boot support being some of the highlights. Since motherboards featuring UEFI are slowly getting more common, it's a good thing the kernel will now be able to boot on those newer hardware.
Unfortunately, Ubuntu 12.04 will not be using this kernel release. We'll most likely be skipping to kernel 3.4 come Ubuntu 12.10.
Check out Kernel Newbies for the thorough list of changes.