Q: How do I add a 'tube' in Blender 2.5, there doesn't seem to be an option for it?
A: At present there isn't an option to do it directly, it has to be done using a "Cylinder" primitive and the "Solidify" modifier.
To do this, first use "Shift+A" to open the "Add" menu, select "Mesh > Cylinder", this adds the needed cylinder primitive at the cursor. This also changes the ToolShelf (on the left) to show some editable options, change where necessary to set out the basic characteristics of the 'cylinder'.
Next click the "Modifiers" button in the "Properties" section and click the "Add Modifier" drop-down, select "Solidify". A new set of options appears. To set the basic parameters of the 'tube' change "Thickness: [n]" (where "[n]" is a numerical value). Using "Offset:-1.000" 'extrudes' the thickness 'inwards' from the outer, initial limit/faces. Once happy with the settings, click "Apply".
