This short walkthrough describes how to install the Ubuntu Linux Kernel 4.2 (server and desktop/client) without compiling.

This guide should work with the latest version of Ubuntu Linux and most Ubuntu-based distributions including Mint. The included kernel files have been compiled using the generic Ubuntu configuration. The general packages are available for 32 bits systems (I386+) and 64 bits (AMD64). I will not provide low latency versions or ARMHF this time.

Installation Guide (GUI)

1. Download the kernel headers package:
   
   http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.2-unstable/linux-headers-4.2.0-040200_4.2.0-040200.201508301530_all.deb
2. And the appropriate package for your system
   • AMD64:
     
     http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.2-unstable/linux-headers-4.2.0-040200-generic_4.2.0-040200.201508301530_amd64.deb
   • I386:
     
     http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.2-unstable/linux-headers-4.2.0-040200-generic_4.2.0-040200.201508301530_i386.deb
3. And the accompanying compiled kernel image
   • AMD64:
     
     http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.2-unstable/linux-image-4.2.0-040200-generic_4.2.0-040200.201508301530_amd64.deb
   • I386:
     
     http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.2-unstable/linux-image-4.2.0-040200-generic_4.2.0-040200.201508301530_i386.deb
4. Install the files in the same order as downloaded above. So first install the headers (2 files) and finally the image (1 file).
5. In the terminal run:
   
   sudo update-grub
6. Reboot and select the kernel from the bootloader menu

I will post the latest version of the 4.2 branch and 4.3 release candidates in comments below.