If there is nobody writing megamenu extension on Yii, you can write yourself. It should be simple. Because you don’t define what you want completely, I’ll assume you are going to put mega menu on every page and the menu is fixed (meaning not url from certain table, or access-related)
I think this is not best practice but it should make megamenu run on Yii:
download the script from megamenu site
put the js file on the your_project/js/ (create ‘js’ folder yourself)
on the your_project/protected/views/layouts/main.php there is code similar like this:
Remember, this is not the best practice, and I haven’t test it myself. But I hope it can run though. If this really have worked, then you should improve the code. Maybe you can convert it into CWidget that will be better