One that I used in both classes last year was Popcorn Picker, which was a big hit with many students in both levels.
Can you provide us with more detail of your lesson plan based on Dan's "Popcorn Picker" activity? I'll post my interpretation later tonight or tomorrow.
By the way, I have been experimenting with using some simple LOGO programming in both levels too.
In (honors) geometry I think I would do a treatment on GeoGebra. My goal being that they leave with a clear understanding of how this program does what it does, keeping straight all of those points, lines and shapes and the relationships between them. For example, when I ask it to draw a circle centered at this point and tangent to that line, what is it doing? I would even bring in a full fledged cad package and show them how heavily geometry based it is, with the additional requirement of organizing all of this descriptive data (points, lines, shapes, etc) such that it can re-render it (or part of it) after each change.