What open-source n-body codes are available and what are their features? I'm interested in doing simulations with large numbers of particles and need a good n-body code.  Are there any out there in the public domain that are open-source and what are their strengths and weaknesses.  I'm interested in all types of codes, ones that can be run on a multi-core desktop for basic simulations and also ones that can be run on large parallel clusters (I have access to both).
For each entry please provide a link and a brief summary of the nature of the code and strengths of the software.  The goal here is to provide a reference list for those interested in the topic.
 A: http://www.supersci.org/Codes.php
Some of those are open source and some not. You'll have to do some googling to get to the useful information, but it's somewhere to start, at least.
A: Amara Graps wrote a good overview of n-body simulation methods.
A: First of all, I do not have any experience with this, I am an Astronomy hobbyist at best.  So I am just going to present what I found with minimal comment at this time.  I found this web page that links to several programs:  http://nbody.sourceforge.net/  They link to the University of Washington and their n-body shop.  I don't know what your status must be to get that software (a student perhaps).
The first link also lists these sources:

Other Astrophysical N-body projects
Integration with work by others is very desirable. Here are some projects we know about. To let us know about others by submitting a new item to the SourceForge Bugs Tracker.
  
  
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*The Nbody Shop - The first software released here has come from this group. The TIPSY nbody visualization program is available from this group.
  
*NChilada - a project to create a parallel visualization and analysis package.
  
*Hubble in a Bottle - a High performance parallel visualization tool. Hosted on Sourceforge.
  
*NEMO - a stellar dynamics toolbox.
  
*GADGET - a freely available parallel code for cosmological N-body/SPH simulations.
  
*SUNRISE - a GPL program to do radiative transfer imaging of cosmological or galactic SPH simulations.
  
*AMIGA - a freely available (GPL) shared memory parallel adaptive mesh code that also includes a group finder.
  
*astro-sim.org - a community site with pointers to astrophysical CFD and n-body codes. 
  

Some additional links that I have found:
http://nbody.softrecipe.com/
Starlab
Gravity 6
I hope this series of links gives you what you want.
