A brief pause here. This isn't how the original Mad Libs was played. A moderator had a whole story written out, with blanks for certain key words. The participants didn't see any of the text.
The moderator would ask for a noun, or a verb, adjective or adverb, one at a time, sometimes with descriptors. Suggestions would be called out, and the moderator would select the silliest one and write it in the blank.
At the end of the game he would narrate the story that the group had "created."
Kinda hard to duplicate that online. The closest might be to list an order of blanks for nouns, adverbs, etc, and have everyone submit suggestions. Then our "moderator" chooses the best ones, and finally posts the completed story. So it might look like this:
Plural Noun -
And so forth. The fun part of the game was in not seeing the sentences you were completing, just supplying words blindly. Here we're seeing the sentences first.