Copied from my post on BitsfromBytes forum as It will be useful for Reprappers with other machines:

I ran off a multipart print today. 16 pieces of identical cable carrier. This was a no raft job on a non heated bed so typically about 20 mins into the job one of the pices came loose and the nozzle glued it onto the next piece writing them both off.

At this point I had the option of letting it run an sitting there with teh long nose tweezers ready to collect all the swirls that were being extruded into mid air where the two pieces should have been, or Option 2. Hit esc and scrap the remaining 14.

I chose mystery option number 3. Which was look at the Z height and bodge together a 3mm piece of acrylic shimmed with some blank business cards and paper. With a bit of masking tape to stick it down to the bed. This gave me the same height as the semi completed prints and I let it run. It worked! The layers stuck and the print continued with no mess, no fuss.

From now on I will have an assortment of shims, blocks and various bits and bobs ready for when it happens again. No more failed multiprints for me.

Following on logically it becomes obvious that we can use this method to support prints!
Imagine prints with massive perfect 90 degree overhangs supported like this. You only need to pause the print before the overhang layer, ( could be done by adding a line of gcode to move the head to home etc). You then add your support to the bed and unpause the print.

Yeah i really like this idea.
It will work well for multiprints
and for big overhangs
and im sure there are more uses.
thanks for the tidbit