Bogosort

Bogosort is an esoteric sorting algorithm that has an average case of $$O(n \times n!)$$, and an unbounded worst case. It is unstable, and not adaptive.

Explanation
To bogosort an array, check if the array is sorted. If it is sorted, terminate. Otherwise shuffle the array and repeat until the array is sorted.

Example
Take the array [2 5 1 6 2 3].

Unsorted: Shuffle it.

[6 4 1 2 3 5]

Unsorted: Shuffle it.

[1 2 6 3 5 4]

Continue until array is sorted.

[2 6 4 5 1 3] [3 4 5 2 6 1]    ... [1 2 3 4 5 6]

Sorted!

Pseudocode
procedure bogosort(array arr) do while not isSorted(arr) do shuffle(arr) end while end