Culver's is a chain of frozen custard and butter burger restaurants located mostly in the Midwest, with a few stragglers in Texas and Arizona. Usually regarded at a step up from other fast food joints, it's also the only place to get frozen custard in a lot of cities outside of Wisconsin.
Just because it might be the only custard place around doesn't mean it's not very good. The shakes are delicious and come in a few interesting flavors, like mint chip and blueberry. Both were made with fresh vanilla custard, though the blueberry was much thicker and made with more custard than the mint chip.
The blueberry milkshake is a standout. There are whole tiny wild blueberries in almost every sip. These berries tint the custard a beautiful lavender color—they taste a bit like blueberry pie filling, though thankfully not quite as sweet.
The mint chip shake is also worth ordering. It's made with mint syrup and a chocolate sauce that doesn't blend in all the way, instead making tiny bits of chocolate throughout the shake, reminiscent of Magic Shell. There's enough chocolate that it doesn't get lost in the mint (but the chunks aren't big enough to clog your straw.)
If you haven't experience frozen custard yet and live in a city with a Culver's, a shake is a great way to kickstart your custard addiction.
Various locations, culvers.know-where.com