"Shovel-ready"?

In today's Doonesbury, Alex describes herself as "a shovel-ready girlfriend".

Maybe I've been reading too much Girl Genius.  (Volume 8 is due for release in May!)  But... Alex is at MIT, yeah, full of Mad Engineering, not so much Mad Science, I thought.  I didn't know that grave-robbing was a big attraction there..?

(I had to do a bit of web searching to find out what the phrase was intended to refer to construction projects.)