Recording screencasts in Linux was a difficult problem faced by many users. recordmyDesktop is a command line tool to record screencasts and it has a GTK and a qt based frontend to make it easy for newbies. RecordMyDesktop can be tweaked to your hearts content by changing the sound and video quality, frames captured per second, mouse cursor style, compression, and whether to record the current window or the entire desktop.
Ubuntu users can install recordMyDesktop and gtk-recordMyDesktop with:
sudo apt-get install recordmydesktop gtk-recordmydesktop
Other distro users too can use their package management tool to install it.