Apple TV on Mac
Ever wanted to run Apple TV on your Macintosh? ATV4mac 1.4.3 lets you do just that–with a few limitations. It's a Tiger-only, Intel-only release. You'll need OS X 10.4.8 and higher and Leopard is a no-go at this time.
With it, you can run Apple TV take 2 as a Front-Row style Macintosh application, which can be a very nice thing if you plan on using a spare mac mini as an Apple TV replacement. Your mileage, as they say, will vary.