I learned this vocabulary strategy a couple of years ago and my kids love being the detectives and figuring out the rule!
Present kids with 5-6 clusters of three words from whatever story or novel you are reading. See if students can figure out the rule that ties them together. Let them guess a few times before revealing the rule.
bonnet, corset, hankie (things you wear)
emigrants, marmalade, silhouette (3 syllables)
hurricane, tornado, flood (disasters)
Your clusters of words probably won't be this different, I just wanted to give you an idea of what you could do.
Some other ideas for rules are plural nouns, places, jobs, etc...
What vocabulary strategies or activities do you use in your classroom that kids find entertaining?