Edit your grub for ubuntu
 

hi...if you're looking for some fun with your ubuntu you can start by editing your grub!!

You can install a background picture and change the colors of letters.
To do this run in terminal

sudo gedit /etc/grub.d/05_debian_theme

And start editing some of the lines. There will a line named wallpaper. You just need to edit that line only

Afterwards save the file and run in terminal

sudo update-grub

Now restart your system

Playing with the grub is fun, but I would not recommend it as long as you know exactly what you are doing.
You might end up with some nasty problems if you do some thing wrong. So please be careful before you edit any thing in grub.