I have a big vat of sour cream in the fridge, and am wondering what to
do with it. And by "big vat", I mean, a Costco-sized tub that could
amply dress a bushel of baked potatoes. I know you can make frosty
desserts from yogurt, so why not from sour cream?

To Google!

An Alice Medrich recipe that sounds lovely, though may depend too
heavily on the sour cream to bring the flavor.

Brown sugar ice cream, sounds good, though it also includes half and
half. I want to use up as much of my vat as possible.

Some fruity options:
Blueberry (just look at that gorgeous color!)

Strawberry

Lemon