Wow...huge teaching resource on the discovery of DNA and the experiments used therein:

DNA timeline (part of the larger, DNA Interactive website)

on the timeline, you can click on any person (or their experiment) and you're taken to an illustrated timeline, then you can click on the person's picture (for a bio) or the experiment (for an animated description of the experiment).

(It's very nice but I do have one minor quibble; on the DNA crystallography experiment the animation looks a bit as if the x-rays are coming out of Rosalind Franklin's head.)