Archaic

Denotes a time of the past, and doesn't speak of happy moments as much as it details foreboding trials and tribulations. Made to use in folk and mystery, often.

Rigorous

Activity - the word that usually follows this adjective. Leaving the reader with a sense of accomplishment, and helping to determine for the reader what exactly occurred.

Earnest

Definitely a positive connotation with this word. There are many ways to express the levels of desire and hopeful effort intoned by this adjective.

Playful

In line with situations that denote joy and mirth, this adjective reads as a mouthful. "Keep it up! Playful pets!" If you want to tell a story of a positive time, tell this!

Laudable

Praise and protection stem from this word in the midst of sentences regarding effect and potency. Long live the days of pristine qualifications!

Wakeful

Restless and alert are what come from this word, "wakeful". Take a moment to determine if your sentence allows for a punchy statement, or just run-of-the-mill.