Instead of just handing out a bunch of capitalization rules to kids, why not have them work together to match the rules with examples using their prior knowledge, hands, and a glue stick.
In this game, students are put in groups of three to five and given a master sheet that is labeled 1-21 and a glue stick. They are also given 42 slips of paper, 21 rules and 21 examples. You can mix them together when you hand them out, so they have to differentiate between rules and examples.
The first part is easy: the students need to paste each rule next to its corresponding number. Then, they have to find the example in the example slips that matches each rule and paste it under the rule that governs it.
To prepare for this game it takes a bit of work, but it's worth it. You need to cut out
a set of 21 rules for each group (keep the number next to each rule on each slip of paper so the group knows where to paste them). Then, cut out a set of 21 examples for each group (don't include the number next to each on these slips of paper. They have to work to find out which rule to paste them under). I included the numbers next to the examples as a key for the teacher.
Have the kids race to get all the rules pasted on with examples that match correctly. Perhaps have a prize for the group who finishes first and has all the answers correct.
When all groups are finished. Write some sentences on the board with capitalization mistakes and have the students approach the board and correct them using the rules they learned.
It's a lot of fun, but can get messy. You can just find a group who put one together neatly , photocopy it, and give it out to the class the next day as a study sheet. The rest can throw theirs in the recycle bin or trash.