FrameBuffer UI
fbui (FrameBuffer UI) is an in-kernel graphical user interface for Linux that sits on top of the framebuffer subsystem. Unlike the X Window System, fbui comes at very low cost: the entire subsystem is about 32 kilobytes in size. fbui permits windows on every virtual console. Each process may access its windows simultaneously with other processes, unlike in X where graphics operations for all windows on a screen are queued and executed by a server. fbui currently does not permit two windows on a single console to overlap.
Included with fbui is libfbui which provides abstractions for windows, events, etc., as well as quite a few sample programs such as load monitor, clock, calculator, scribble pad, image viewer, window managers, and a simple MPEG2 player.