Think of build your own Arduino case? With some LEGO blocks you can build it yourself easily. Below is the picture of the Arduino UNO inside a LEGO case:
You can use any colour you like to build you own Arduino LEGO case that suit your Arduino board.
If you want the easy way out just buy this Arduino UNO plastic case from Amazon which also provide a space for your 9v battery cell and a shield for your Arduino UNO.