Last night, I saw 54-40 at a free concert in Colonel Samuel Smith Park. They sounded great, playing all their hits (and there were many) and we had a blast.
It was this little dude's first concert.
As a kid, I saw several "free" concerts at the old Ontario Place forum, but you had to buy tickets to the park to see the show, so it wasn't really free. As a young man I biked to Yonge and Dundas to watch Sloan perform a free concert outside the Edge 102 studio. I thought that was pretty awesome.
What's the best free concert you ever attended?