I've heard "mountain" or "prairie" oysters more often, as well.
Ate them, once. I had joined the local fire department (their first female member, actually) and every year we put on a shindig for the other departments in the area. Two of the members are country veterinarians.
They saved up all the testicles they cut off the steers over the last number of weeks before the dinner, and they dredged them in flour and dunked them in some sort of batter before deep-frying them.
How'd these taste? Well, they were a bit chewy in texture; they reminded me and my husband of clams. Sorry, not chicken-y at all. Just a bit rubbery, but not too much. Not even as rubbery as calamari are. Just . . . chewy. And not bad.