The Hamilton Harbour/Waterfront is a great idea! Especially with the great weather we've been having.
Also, there's an aviary right near Mac and some other trails although they're probably pretty muddy right now.
Don't forget about the Get Cultured initiative which allows you to get into all of the museums in Hamilton for free with a student card.
And you can borrow movies from the library for FREE! They don't always have the greatest selection, but if you plan ahead you can request certain ones.
Those are my ideas right now, hopefully some other good ones will come up cuz I've been looking for new ideas too