When I arrived at my current school, there was no written curriculum and very little left by my colleagues as a framework for my lessons. There were, however, high school classes that my students would be offered at the end of 8th grade and I decided to focus on preparation for the programming courses. I needed a piece of lightweight, easy to use software that could illustrate basic concepts such as sequencing, conditional statements, and (most importantly) debugging.
XLogo is a terrific tool (for Apple OSX only, however) and fits the bill nicely. Students can create and save simple programs (drawing a square, for example) very easily, making XLogo very easy to introduce. More complex programs (drawing a donut) are saved just as easily, making it possible for students to focus on their programming skills rather than the software itself.
I used XLogo extensively in the 7th grade that first year, but when I passed that curriculum on to a colleague, it was dropped from the 7th grade program. This year I am focusing on 8th grade (where we already work with Scratch), and I am planning to reintroduce XLogo as an introduction to Scratch. Can’t wait to see how that goes!