As part of my lesson on homophones, I use this PowerPoint as a review of synonyms and antonyms and as a checking for understanding for homophones...
Pairs of words are given and students must choose if the words are synonyms, antonyms, or homophones. If they are incorrect, it take them back to a screen that tells them to try again. If they are correct, it lets them know, and then takes them to the next pair of words.
An Activboard is not required, but If you have one you can let student volunteers come up to the screen to work through the slide show.