An aux track is a track that you can send the output of another track or tracks to. It can work in a similar manner as a buss for creating a submix. For instance if you have a recorded snare and a snare sample, you could route them to an aux track to create a submix. The benefit of using an aux track is that you can organize the aux track so it is next to its two (or more) input tracks in the track view or console view.
A patch point is a routing point which you can route an input from or an output to. An example would be say you want to get that ultimate guitar tone using multiple amp sims on the same guitar part. You could route the output of your DI'd guitar track to a patch point. You could then create several tracks with different amp sims on them and route their inputs to the same patch point. To wrap it up you might even route outputs of the amp sim tracks to an aux track to create a submix.
There are probably other uses for aux tracks and patch points, but those are two I have used before.