When I was in high school (Mandeville High), on the northshore, we could also get some of those big swells when the wind was right. We'd float on inner tubes, and try to be in the right spot where the incoming and "bounced-back" outgoing swells would meet.
I've taken my Adventure Island out of the Mandeville Harbor a few times. I was always sure to check "weather.com" for any potential changes in the weather while I'd be out. I know things can change quickly.
I'd love to see more AIs on the lake. I'm thinking of bringing one of my Maryland-based AIs to Mandeville, hoping to sell it just to get another AI on the lake. Massey's Outfitters (Hobie dealer) is right outside Mandeville, so it'd be nice to get something going.