There was also http://www.sagemath.org/eval.html in the beginning which I actually quite liked because of its simplicity. The heavy featured dead site got dead because it was unmaintained and spammed.
In any case - it would be absolutely fantastic to have some neat and easily searchable/submittable site. But I do not volunteer to set it up. If anyone else has time/desire/grant/etc please speak up or even better - get busy!