CBS Big Bang Theory Season Finale a cliffhanger

CBS prime time hit comedy Big Bang Theory ended with a big cliffhanger in its season finale Thursday night. PHOTO CBS.com

CBS prime time hit comedy Big Bang Theory ended with a big cliffhanger in its season finale Thursday night. PHOTO CBS.com

In what could be the slowest moving relationship in television history, Big Bang Theory's character Sheldon took a BIG leap forward and proposed to his long time girlfriend Amy.

The proposal came in the last minutes of the season finale after Sheldon traveled to Princeton where Amy is on a work assignment.