Anybody do them without using the specialized machine for them and without stacking an olympic barbell full of plates on the ground?  

If you do/have, let us (me) know your solution!

The best I can come up with is a back hyperextension machine adjusted to its lowest level (but that still puts your hamstrings at 45 degrees instead of parallel to the ground).

Glute Ham Raises...

http://www.exrx.net/WeightExercises/Hamstrings/BBGluteHamRaise.html
(with a machine)

http://www.weighttrainersunited.com/gluteham.html
(again, with a machine)

http://www.t-mag.com/nation_articles/260rm.jsp
(no machine, but needs a partner and little use of glutes)

http://www.kvusa.com/wl/floorghr.htm
(no machine, but uses a barbell on the floor which could be a no-no in my stupid gym)

I use a bench with knee pads made to hold you down while doing lat pulldowns.  I put my calves under the pads while facing towards the rest of the bench (and away from the cable) and do them.z