If you are with kids,there are some places to go such as 1) www.CanadasWonderland.com in the north of toronto;2)Toronto Zoo(east of toronto)3)wild water kingdom;www.wildwaterkingdom.com 4) Ontario Science Centre and royal museum5)CN tower(downtown) and etc.
If you live in west of Toronto i.e mississauga, you are more close to Niagara falls, one hour drive.