I appreciated all the upbeat entries! Many good candidates, which I judged subjectively for how they exuded the topic, and for photo quality.
Some honorable mentions I really enjoyed:
In third place, with a great unbridled expression of glee, from Robin Lew:
In second place, the special glee of a child, from Ken Zaret:
In first place, from Walter Koenig, a very colorful character with what struck me as a very genuine, contagious expression of glee: