This is the time of the year (at least in the USA) when everyone should take a moment and think about for what they should be thankful. For many it is their family and their opportunities. One thing that any decent technologist probably has had at one time or another is a good mentor.
We have many managers, colleagues… we may not remember all of these, but we do remember the relatively few mentors (at least in my experience) that touched our lives. The mentor role is almost always voluntary (unlike coaches). They expose part of themselves to others, as a way to avoid or at least share some of their experiences along the way. They make this investment without the assumption of a return, other than the experience of sharing with others.
The best way to show thanks is by finding someone else out there who needs a mentor and just give… you will likely gain from the experience too since it is almost always a two way street.