Really nice utility if you have a Columbus 900 GPS Logger. I have one and I had to do many conversions before just to use the tracks recorded on a map. Now, with Columbus Viewer, I just load the original files from the logger and I can see the track on a map, elevation data and speed in a graph with some compiled info. Really nice and free.
I am in no way affiliated to Columbus or to this software, but I do recommend both of them if you are a Mac user that likes outdoor sports.