"Dead simple and free, what more could you ask for? - LifeHacker
Also featured on Android Community, Talk Android, IntoMobile, Android Headlines, and Droid Life!
Fast, Simple, Elegant
A homescreen widget to show messages (or SMS) received in Google Hangouts
Fully resizable and shows your messages at a glance.
Because of limitations to the Android system, only new Hangouts will be shown and only works for 4.3+
You must first install Google Hangouts! :)