The Minimig is the Amiga 500 clone that shock up the Amiga world by storm in Amiga.org during late summer 2005 to the point some members questioned if the project was a prank. It was not, it is actually possible for a single guy to design and create an Amiga 500 clone all by himself.
The Minimig is not however 100% compatible with an Amiga 500 so some applications and games does not work but Minimig is work in progress so the list of working applications and Amiga games is by no means definitive.
Check out the Minimig compatibility database
And if you begin to salivate over a Minmig (I know you want one) check out Acubes or Amigakits homepage!