it's a simple testobject made in Blender 2.5... http://Blender.org

this thing should have 2cm x 2cm x 2mm

to make this thing in Blender 2.5:

its the default cube in the default szene.

select the cube > Tab (to switch in editmode) > select the upper Face > press G Z -1.8 Enter (-1.8mm allong the z axis) > press S for scale and type 10 and Enter (1 Blender unit is 1 mm)
save this as *.blend file (ctrl+W)

permanent STL Export:
go to user preferences (ctrl+alt+U)... klick on Add-Ons > Import/Export > check mark Import/Export:STL Format > close this Window > then press ctrl+U and Enter

Export your Blender-thing:
select the object('s) you like to Export > go to File > Export > STL

your default screen is now this little thing... to start without any objects in your default szene press A(de/select all) X Enter to delete all > again press ctrl+U and Enter

now you have a clean workspace to start new things from scratch each time you start Blender :)