Changing Ubuntu's splash screen

If you installed Ubuntu and Kubuntu on the same machine you can chose the splash screen by:

sudo update-alternatives --config usplash-artwork.so
sudo update-initramfs -u -k all

Starting VNC to an already running X server

If you have to access your desktop remotely, but the only connection what is available is ssh, then you can start VNC attached to your running X session by

x11vnc -passwd somepassword -display :0 -auth /var/lib/gdm/:0.Xauth

(This supposes that you use gdm.)

Modify keyboard volume key steps

To adjust the percentage of the volume up/down multimedia keys steps use gconf-editor and navigate to /apps/gnome_settings_daemon/volume_step.