https://launchpad.net/algorithms-animator
A little advanced but might be a able to use this with a younger group.
“Python application that implements and animates interactively those algorithms that are normally covered in an undergraduate course on the topic. It includes Insertion Sort, Quicksort, Mergesort, AVL Tree Search/Insert/Rebalance, Depth First Search, Breadth First Search, Topological Sort, Prim, Kruskal, Dijkstra, LCS, Huffman-Fano, and more. It is extensible. All the API are exposed. It includes a ready-to-run Windows executable (bin/AlgorithmsAnimator.exe), some documentation and a short tutorial about running time analysis (doc/csc321notes.pdf). This program was originally designed in 2003 for teaching “Design and Analysis of Algorithms” at DePaul University. All the algorithms in the source code (src/csc321algorithms.py) are equivalent line-by-line to the pseudo-code in the MIT CLRS “Introduction to Algorithms” book.”