Taking Advantage of Prone Enemies

[sjeshin]

There are a lot of awesome ways to get enemies prone. Trip, overrun, and spells are a few ways. Are there any ways to capitalize on prone opponents more than just getting a better shot at hitting them in melee? Are there any feats / special attacks / spells that may be sub-optimal, but do work well at capitalizing on having your enemy prone? For example, are there any feats that make you do more damage to an enemy that is prone?

[Geddy2112]

There is vicious stomp, which allows you to make an unarmed AOO against any opponent that falls prone next to you. This stacks with greater trip so you can trip somebody and then get 2 strikes in on them. Shame a fair amount of enemies are hard or impossible to trip.