I go to Venice quite a bit for horse shows, there is a great resturant called Sharkey's out on the beach, at the Venice peir. The kids can stay busy digging in the sand looking for shark teeth, ask anyone what they look like because they kind of look like small sea shell bits.
I have never found a place there to rent cats, or any other sailboats, BUT, if you drive north on 75 to Sarasota, get off at Fruitville Road, go west over the big bridge and out onto Lido Key, go around St. Armond's Circle (do NOT stop to let mom out to shop...) then turn south along the public beach, at the south end of the key there is a big hotel on the right that has some Hobie Waves parked out back for rent. I think they want about $30/hr. for them but it's been a while since I was there. Good luck.
Oh, also for the kids, you can go back to the circle, exit going north, go about 2 miles and turn right onto Radio Road just before the bridge over the cut to the bay, down there on the right is Moat Marine Aquarium. They save Dolphins, sea turrles, etc. and you can watch. My kids loved it.
Then keep going to the end of Radio road and there is a park with swings, etc. for the kids, and a small beach on the bay side. And on the north side is the Sarasota Sailing Squardron, a great place to grab a cold one and walk the yard looking at sailboats.
Venice is nice but not a lot to do there. Sarasota is nicer but much more crowded and more expensive.
