So, I'm a geek, but I just figured this out and think it's damn cool.

Adverb: an ADjective acting as a VERB (or relating to the verb as opposed to the noun).

Soft (adjective): The soft bunny was sleeping. [The bunny was soft]
Softly (adverb): I pet the bunny softly. [The pet was soft]

Happy (adjective): The happy boy grinned. [The boy was happy]
Happily (adverb): The boy smiled happily. [The smile was happy]


Shut up, I'm working on my grammar skills. Bleh to you all.