A golden opportunity
A perfect, maybe one in a lifetime chance
Wild goose chase
Daily Double: Once in a blue moon
Very rarely
Birds of a feather flock together
people who are alike often hang out
Don't rain on my parade
Don't spoil my good time
The way the cookie crumbles
That is just how it is
Get the green light
to receive permission to do something
Black sheep in the family
outcast or outlier of the family
Daily Double: Under the weather
To feel mildly ill or sick
Kill two birds with one stone
To solve two problems/take care of 2 tasks with one action
Daily Double: Bite the dust
To die or be defeated
Upset the apple cart
To interfere with a plan or progress
Daily Double: White elephant
a useless, cumbersome or unwanted possession
A bee in your bonnet
To be obsessed with an idea
Dog days of summer
the hottest and most humid days of summer