Google adds some fun live effects on video chats made from Google Talk on Android devices. This feature is available for ICS (Ice Cream Sandwich) version and later (Jelly Bean)
You can change the background behind you during the video chat. You are also able to have some funny faces with effects like big mouth, big nose, face squeeze and more.
In order to apply these live effects, just tap on the corresponding button during the video chat in the Google Talk application