take potluck

(take) potluck (with sb) (to come to eat whatever food happens to served or available for a meal, especially when offered to a guest) — (пообедать, поужинать) чем бог послал; разделить трапезу с кем-л. ; (ср. чем бог послал, чем богаты, тем и рады {pot-luck угощение для нежданного гостя})

Example 1: You are welcome to stay for dinner if you will take potluck.
Example 2: Having arrived unannounced for supper, we had to take potluck. (yourdictionary.com)

a potluck party/dinner/etc or a pot-luck party
(a meal/party at which everyone brings food or drinks to share with everyone else; a meal/party at which each guest brings food that is then shared by all) — (обед / ужин / пикник / пр.) вскладчину {когда каждый участник приносит заранее оговоренное блюдо или напиток}; потлак
have a potluck (party/dinner/etc)

Examples:
..... We went to a pot-luck party and I prepared fried chicken for everyone.
..... We are having a pot luck on Friday and we'd like you to come. We still need someone to bring a salad, drinks, or a dessert. If you want to come, please let me know which you are going to bring. We already have enough people bringing main courses.
(english-test.net)
.....Turning your party into a potluck is one way to save yourself a little trouble. At potlucks, each guest brings a dish to share with everybody. That way, there is plenty of food and a lot of different options for everyone at the party to enjoy. But if you decide to host a potluck, you might want to give your guests some guidelines about what to bring. Otherwise, you could end up with nothing but dessert, or a bunch of different versions of the same boring casserole. (englishbaby.com)

(take) potluck (on sth) (to accept or choose from whatever is available, without knowing whether it will be good or not) — довольствоваться тем, что есть, что подвернётся, что посчастливится достать, что останется и т. п.; сделать что-л. наудачу

Example 1: The scheduled flight was canceled and passengers had to take potluck on the other airlines.(yourdictionary.com)

Example 2: We'll take pot luck at whatever restaurant might still be open. — ... перекусим / поедим где получится (где удастся, где открыто и пр.) (Collins Essential English Dictionary)

Example 4: If you haven't made an appointment, take pot luck and knock on the door.

pot-luck approach

Example: He scorns the pot-luck approach.

Related vocabulary:
take one's chances

Origin
This idiom alludes to accepting whatever happens to be in the cooking pot. (The American Heritage Dictionary of Idioms by Christine Ammer)

The expression is still used in its original literal sense as well (to take one's chance or luck as to what may be in the pot, cooked for a meal, as distinct from what is specially cooked for a guest). There may also be an allusion to the use, in peasant cookery, of a stew-pot or stock-pot to which is added each day whatever happened to be ready from the garden or market.

See also:
[hog and hominy]