have you thought of making up custom 'flash cards? (use a computer, and card stock, and a paper cutter)

side A the prefix/suffix/root (un, dis, ex, ing, ed, tion, etc)
side B a definition of the prefix/suffix/root-- (make up a few sets)

some times a prefix can mean several different things.
take A (amoral) A means Not/lacking (amoral is lacking morals)

but A in arise, awaken, has a totally different meaning!

does ing always make a word into a gerund? (what is a gerund?!)

let the kids try to figure out what the word means (based on the clues the cards provide).

(have some blank cards for root words.. )

you could divide the class into teams. and see which team come up with the right meaning.. each team gets points. (which are worth nothing or worth a 'crown of olive leafs' or something else valueless.)