After being beaten in a minigame, or joining a server mid-game, you enter spectator mode. In this state you get to watch the players continue the game until the end.
Not many know there are actually two spectator modes, which can be toggled between by double tapping the Interact key, which is bound to the left mouse button by default.
Spectator TV
Spectator TV attempts to automatically follow the action in cinematic fashion.
Freecam
Freecam allows you to freely look around in 3d space without collision.