If you are familiar with Black Holes, maybe you don't need to read through this post at all and you can do something else with your time.
If you are not and haven't read much about Black Holes, then you might want to read slowly and ponder on some of the finer moments. I will try to provide information as scientifically correct and pictorial as possible. Please note, that at times it might be good to additionally Google some term.
If you know much about Black holes, but are not sure if you're missing details, then check it out; something interesting might pop up.
1. A bit of Info
The crunched electrons will fuse with protons and form a degenerate matter made predominantly of neutrons. A neutron is heavier than a proton(and can decay into a proton by emitting an electron and an electron anti-neutrino or a positron and an electron neutrino--not so important!). In either case it loses mass and energy.
Alas, if gravity is powerful enough, the state of a Neutron star lasts only for some seconds. If the crunching continues, the entire mass will get smaller and smaller until it vanishes from sight. Observed from far away it will be as if it has faded from view. Steadily the Event Horizon will emerge--the shadow of the Hole. Its size depends on the mass of the matter being "crunched" together.
Now there is no matter to speak of any more. The entire Singularity is formed of curved space-time into infinity. The current understanding of physics calculates infinities when trying to resolve numerically the state of the Singularity. This means that we don't really know what's at the centre (although there are some very interesting speculations!).
To make things a bit more pictorial, imagine you standing in your back yard with a wide net stretched thin. You throw a stone as hard as you can and the stone bends the net, for a moment the two dimensional plane of the net is "twisted". It has curved into a three dimensional object. For a tiny ant living on the two dimensional plane of the net, it might seem that the plane is still flat when it is walking about, but to us--we see the entire picture easily.
Of course, after a short time, the net will push the stone back and it will return to it's state of minimum energy(being stretched and at rest). But imagine if the stone was stretching the net into infinity. Look at this picture to help you imagine.
From the perspective of a two spatial dimensions we can easily imagine what exponential curve of space looks like. Now try to think about what an infinite curve would mean in three spatial dimensions, like our universe.
Having difficulties? No worries. Science also has not evolved enough to make absolute sense out of it. For all we know, we have not yet observed a Black Hole(or rather its Event Horizon) directly.
The last boring information I will add before continuing is that unlike the net from our earlier scenario the Black Hole Singularity will take a lot more time to "unfold". Physicist Steven Hawking predicted that Black Holes evaporate slowly, but that is to be confirmed by observations in the future. His name will probably be awarded with a Nobel prize in the future.
Also, unlike the net, the Singularity is staying in this "maximum" state of curvature, simply because it is in a "maximum" state of curvature. That is, the twisted space-time is supporting its own structure, despite the enormous energies involved into "folding" it in the first place. The stone is staying in the net, stretching it into infinity and you don't know exactly how far away that is from you.