nVidia Optimus on GNU/Linux.
Features

    Full independent 3D on both video chips.
    Auto power off for second X-server and nVidia chip.
    Easy installation (look at Wiki).
    Multiuser access.
    Run in a way nvrun app.

Tested distros

    Gentoo amd64
    Debian Squeeze amd64
    Debian Wheezy amd64

Supported Models: M11XR2, 1015PN, 1215N, K42Jc, K52Jc, N53Jf, N53Jg, N71Jv, N73Jf, P52Jc, PL80Jt, U30Jc, U33Jc, U35Jc, U36Jc, UL80Jt, N53Sn, U41Sv, N53Sv, N61Jv, N73Sv, P31Jg, U43Jc, UL30Vt, E6420, InspironN5110, XPSL702X, Vostro3300, Vostro3500, XPS15, ThinkPadT410, ThinkPadT420.

Video on YouTube: http://www.youtube.com/watch?v=c6RH69j-gMY&feature=plcp&context=C3f5cbeeUDOEgsToPDskLOX8DnELkwYsi2QZ7_phwJ