The first 11 Doctors from the Doctor Who series are represented here. There's also the TARDIS, of course, even though that's not crocheted. My hat (or my fez) is off to the person who designed and crocheted all of these Doctors!
Desiree Yang, who just graduated with a PhD from Tom Bernhardt's lab at Harvard, made this really awesome set of crocheted E. coli as a present for her thesis advisor. It shows the stages of cell division, with the Z ring embroidered in green