Programming Praxis http://programmingpraxis.com/2013/05/03/pairing-students/

Pairing Students

(defun create-pairs (lst)
  "given a list, produces a list of all possible sets of pairings, without duplicates. "
  (if (eq lst '())
      *pair-list*
      (progn 
        (dolist (item (cdr lst))
          (push `(,(car lst) ,item) *pair-list*))
        (create-pairs (cdr lst)))))

(defvar *pair-list*)
(let ((*pair-list* (list)))
  (create-pairs '("Anne" "Beth" "Chet" "Dirk")))