I do a lot of projects with Arduino's and breadboards. Often as I work on a messy workbench, the Arduino or breadboard get jostled and the wires pop out of the headers or the breadboard. To solve this problem, I decided to make a simple acrylic stand for mounting an Arduino and a breadboard that would prevent them from moving around.
I used a laser cutter to cut the acrylic to size, to cut the holes for mounting the Arduino and to engrave a rectangle on the base to help align the breadboard. Don't despair if you don't have access to a laser cutter: you could use a saw to cut the acrylic and a drill press to drill the holes.
There are two versions of the stands: one for the Arduino Duemilanove and Diecimila and one for the Arduino Uno.
The photos show two views of an Uno stand made out of clear acrylic and a Duemilanova stand made out of blue acrylic
I made this at TechShop
in Menlo Park.