Coding this from scratch is not that easy, and it entirely depends on the complexity of the obstacle. If for example you know the obstacle is only ever a single circle, then you can do something quick and cool like detecting when the object is within the radius of the circle, then plotting a new path to skim the edge of that circle and then a second point to the original destination (using a simple state machine). I am sure a fellow AppGameKit user can knock up a simple example of this to get you started thinking about the intricate world of path-finding!
I drink tea, and in my spare time I write software.
