An article on slashdot had a comment that linked to The Merger of the Milky Way and Andromeda Galaxies that has a movie of the two galaxies colliding. John Dubinski used a super computer to simulate the two galaxies with about 100 million partials.
I had seen this movie before and it stuck with me. Last year I wrote a small gravity as an exercise in learning C#. On my AMD XP 3000+ with a gig of ram I was only able to work with about 50k partials before the calculations where too slow to wait for. Still it was a fun exercise. And now I've got the link that inspired me.