hamburger is derived from the town of Hamburg which, we're told, has nothing to do with ham. Or does it?
The OED says ham "the thigh of a slaughtered animal" is from ham "the hollow or bend of the knee", apparently from Proto-Germanic *ham(m)- "to be crooked". Skeats derives this from the Proto-Indo-European root *kam- "to bend". Nowadays this is written as *kamp- and might be the source of gam "leg" and jamb, both from French.
Assuming that ham is from an earlier form meaning "to be crooked" or "bend", then it's tempting to say that Hamburg was named because it is a burg at the ham, or bend, of a river.
But the AHD says English ham is from Proto-Indo-European *konh₂-mo- "shin, leg, bone". In that case the Proto-Germanic form was hamma- meaning "leg", not "crooked". Although it's plausible that the "leg" sense changed to "bend" at some point, and that this sense could be the origin of Hamburg, but I'm just speculating now.
Another possible derivation is German dialectal hamm, which according to Grimm means "meadow, forest, house, yard" in Frisian and Lower Saxon.
*konh₂-mo- gives us gastrocnemius from Greek κνήμη "calf of the leg" (plus γαστήρ "belly"). gastrocnemius is the calf muscle that sticks out, like a belly.