I've been playing around with The Ditherinator, and I love it. Lets you... well, dither images. With custom colour palettes. Like, a one-bit palette and the Atkinson algorithm from the original Macintosh: Or maybe you were more of a CGA type, with the Sierra algorithm? And it's amazing how far the EGA palette stretches with a bit of Burkes:
I was just about to come here and post how I don't need software to help me procrastinate, I'm already an expert at that Loving those pictures, getting a real nostalgia kick. What it really needs, though, is a bit of animation at about 1-2fps