Comment by X4

   *  Sabayon - It's a better experience than pure Gentoo
   *  SliTaz - You won't believe me how insanely fast it is!
   *  Peppermint OS - Perfect for mum and friends

Busybox Kernel, 35MB, but fully featured http://www.slitaz.org/en/

Ubuntu based, but much faster and less distracting http://peppermintos.com/

The perfect OS for a developer/sysadmin who is thrilled for more http://sabayon.org/