Well, that's the end of Nichijou

The finale of Nichijou features a plan to surprise Nano for her birthday. While it isn't really Nano's birthday, Mio and Mai go along with Yuko's idea because it will still be a nice surprise for Nano.
Professor tells Nano that morning that she has mad a small version of her screw that she will replace the normal one with. Nano is over joyed until Sakamoto steps on it crushing it. Professor says that she'll have a new one made in no time, and puts Nano's original screw back on.
At the end of the day all of the girls meet at Nano's house. Professor takes off Nano's screw and hands it to her. As Nano goes to store it somewhere, she realizes that having the screw the entire time HAS NOT prevented her from making friends as she was so worried about. Yuko treated her as a normal girl from the very beginning and even at the sight of Nano with one of her hands detached, Yuko never treated her badly. Nano has made some amazing friends despite the presence of the screw, and she may have not made them had the screw not been present.
When the girls arrived yelling "Happy Birthday", Nano was so surprised but ecstatic. Today actually WAS her birthday and her friends had remembered. Nano put the original screw back on. When Professor came to replace it with the small screw, Nano began to tell her that she wished to keep it on, but Professor removed it, put in the small screw, and then replaced the original screw on top of it. Professor said that the small screw would allow the entire piece to spin when Nano was really happy, and it spun for the remainder of the episode.
This was a very heart warming episode and a wonderful conclusion. Although it very much pains me that this is the end of the show.