You can install the mainline kernel from the ppa

http://kernel.ubuntu.com/~kernel-ppa/mainline/

Or you can compile it yourself

https://help.ubuntu.com/community/Kernel/Compile

The problem you are going to have with those options is twofold

1. Neither the mainline kernel or compiling a newer kernel are going to have the standard set of patches Ubuntu applies, most notable is Apparmor.

2. Any packages that depend on the kernel, Virtualbox, nvidia, wireless, etc, might not work.

You would need to debug those things yourself or wait for the Kernel team to release an updated kernel. Support for the mainline kernel or custom kernel is limited, more so for third party packages such as virtualbox , nvidia drivers, etc.

I am not trying to either encourage or discourage you, just pointing you in the right direction. I have been using a custom kernel on gentoo for almost 2 years now, but doing so requires a moderate amount of effort on my part.

From the kernel team FAQ

The mainline kernels builds are produced for debugging purposes and therefore come with no support. Use them at your own risk.

Your other option is to build a custom kernel. This is also poorly supported and requires some advanced knowledge

See https://help.ubuntu.com/community/Kernel/Compile

Building and using a custom kernel will make it very difficult to get support for your system. While it is a learning experience to compile your own kernel, you will not be allowed to file bugs on the custom-built kernel (if you do, they will be Rejected without further explanation).

Your best option may be to install 12.04. Be warned it is in beta at the moment, you might want to wait for the release.

• You may be better off filing a bug report

How do I report a bug?

This answer is obsolete for modern Ubuntu releases

Without the extra package, most hardware won't work!

It contains extra drivers left out of the base kernel package; install it only if you need these drivers

Sometimes, a specific variant of the linux-image is slimmed down by removing the less common kernel modules (drivers). In this case, the linux-image-extra package simply contains all of the "extra" kernel modules which were left out.

• Officially, this only happens for the -virtual image; the most common hypervisors (Virtualbox, VMWare, Xen, KVM) emulate a well-defined and restricted set of hardware, so removing unnecessary drivers which increase the size of the kernel/initrd is a good idea. You can always get them back by installing the extras package.

• The kernel team also appears to have adopted this method for some of the mainline-PPA -generic kernels; the reasoning and solution remain the same -- if it looks like the base kernel image is missing a module you need, install extras.

• As far as I know, the above approach has not been taken for the Quantal kernels -- only -virtual is affected as usual.