I am trying to insert blocks into a drawing but they don't show up. I don't get an error, they just don't show. They work and display fine in other drawings. This particular drawing I started from a template and have xref'd 2 drawings in. The drawings were originally .dgn's. Layers are on, nothing frozen in viewport, etc. This is driving me nuts so any help would be greatly appreciated. FYI, Civil 3D 2011. Thanks.
Try using the 'mapimport' command. That tends to hande Microstation data a bit better.
If you go to the block editor (type blockedit or be) do you see the name of the block(s) in the list? If so pick it and see what is in the definition in the drawing. Maybe the lines are created on a layer other than 0 that is currently frozen in your drawing.
Zoom extents and see if the block has somehow given itself a funky insertion point that is off in space. I've had that happen with the dgn-originated drawings before. If that is the case, edit the block and give it an insertion point.