Now, this is a superior comedy anime which talks about day to day dramatics of 3 sisters in modern Japan. I consider this anime as superior than vastly over hyped Lucky Star in terms of pacing, comedic delivery and characters.
I would heartily recommend this anime to anyone who is looking for light comedy and well done anime. But for people looking for plot and development, forget it.
Best way to imagine it is Azumanga Daioh mixed with Ichigo Mashimaro.
Sample jokes:
Tsukkomi: "What is a thing that be seen when you sit and disappear when you stand up?"
Bokke: Erm, errr.....pantsu?