Black holes "regurgitate" Do Black holes "regurgitate" their contents at some point or do they simply grow larger as they "suck" in more matter? Also, is their bottom (if they have one) "capped" or is open to expel the matter they contain?
 A: For the most part a black hole can only grow; nothing (not even light) can escape. The only exception I'm aware of is Hawking radiation. Briefly, this happens when virtual particle-antiparticle pairs are created very close to the event horizon. One of the pair ends up inside the black hole, while the other escapes (both particles become "real"). Conservation of energy requires that the particle that fell in have negative energy, so the black hole loses mass when it accretes it. This obviously involves some fairly advanced/exotic physics, but the general consensus seems to be that the idea is sound. Eventually Hawking radiation leads to the complete evaporation of a black hole, but this process takes a very long time - for a black hole with the mass of the Sun (a typical small black hole), the evaporation time is more than $10^{50}$ times longer than the current age of the Universe.
As to having a bottom/cap... a black hole is not a hole like a pit. It is an extremely dense object from which nothing can escape. The heart of the black hole is the singularity, thought to be a lot of mass existing at a single point (or something like that, the singularity is poorly understood since conventional physics cannot describe it). The edge is the event horizon, which is the "point of no return"; once a photon or particle crosses the event horizon headed in, it cannot head out again (except as described above).
