Golly is an open source, cross-platform application for 
exploring Conway's Game of Life and other cellular automata.

Golly's key features:

- Supports bounded and unbounded universes, with cells of 
  up to 256 states.
- Supports multiple algorithms, including Bill Gosper's 
  super fast hashlife algorithm.
- Many different types of CA are included: John von Neumann's 
  29-state CA, Wolfram's 1D rules, WireWorld, Generations, 
  Langton's Loops, Paterson's Worms, etc.
- The RuleTable and RuleTree algorithms let you plug in new 
  rules.
- Responsive even while generating or garbage collecting.
- Reads RLE, macrocell, Life 1.05/1.06, dblife, and MCell 
  files.
- Can also read common graphic formats: BMP, PNG, GIF, TIFF.
- Can extract patterns, rules and scripts from zip files.
- Can download patterns, rules and scripts from online archives.
- Includes a state-of-the-art pattern collection.
- Can paste in patterns from the clipboard.
- Unlimited undo/redo.
- Configurable keyboard shortcuts.
- Auto fit option keeps patterns sized to the window.
- Full screen option (no menu/status/tool/scroll bars).
- Supports multiple layers, including cloned layers.
- HTML-based help with an integrated Life Lexicon.
- Scriptable via Perl or Python.