Byzanz is best way to record GIF on ubuntu, only disadvantage is that its command line tool (to few like me, this is an advantage )
Simplest way to create GIF
byzanz-record --duration=5 out.gif
Now if you want to add delay of few seconds
byzanz-record --delay=5 --duration=10 out.gif
If you want to record specific dementions ?
byzanz-record --duration=15 --x=200 --y=300 --width=700 --height=400 out.gif
Here is sample recording