a movable feast

a movable feast

something that happens often but at different times so that you are not certain when it will next happen They usually have a party at some point in the summer but it's something of a movable feast.
See also: feast, movable
References in periodicals archive ?
The term "heartlands" seems to be a movable feast and can be defined as anywhere that Plaid can jump on a local bandwagon.
In the early church 2,000 years ago Easter was linked to the Jewish festival of Passover, itself a movable feast.
Who doesn't enjoy a movable feast or old-fashioned picnic?
Many of you will have wondered why Easter should be a movable feast (rather like my supper, which depends upon the mood and whim of the Dragon Lady).
THE date of Passover is variable as it is dependent on the phases of the moon, and thus Easter is also a movable feast.
As 501(c)3 charitable institutions, think tanks are not bound by hospitality restrictions, and so can offer public servants a movable feast of fancy policy-seminar lunches and all-expense-paid fact-finding trips to foreign countries.
His eighty-fifth birthday last May was a movable feast, celebrated in New York City, San Francisco.