What are some non-tourist things I should do in Rome, Florence, & Venice?

I'm going to Rome, Florence, and Venice, and I have tours booked for the really tourist-y stuff...(the vatican, etc) but....

I really really like doing things other than just the toursity stuff so I can actually experience the place I'm visiting when I'm on vacation.

Do you know of any good restaurants/places to see that are more a local thing and not so mainstream, in any of these cities?

Thanks so much for your help!
I agree with you, the best experience is going off the beaten track. I???ll try and give you a few tips.
Venice: take a boat ferry to Murano and visit the glass blowing laboratories, then have a typical fish lunch in one of it???s trattorie. Travelling from Venice to Florence, if you can, stop over at lesser known but equally fascinating places like Padova, Ferrara and Bologna, rich in art, cultural heritage (Ferrara is a Mediaeval jewel with it???s own castle) and rich cuisine. In Florence, take a trip out to the surrounding hills, either to nearby Fiesole (nr. 7 bus, Etruscan remains, Villas and other sights and, here again local fare is very tasty) or to San Gimignano (the Mediaeval Manhattan). From Florence to Rome there is either Perugia or Siena both unique and worth seeing. Once in Rome, go to the locals' favourite quarters, Trastevere (Ristorante il Buttero via Lungaretta) or the old Vatican quarter (Ristorante Ristochicco, Borgo Pio) in order to see the Eternal city through Roman eyes. Then take a trip out to the Fiumicino fishing village and see the boats coming in with their early morning catch (tube + bus). You can have a tasty fish lunch at Bastianelli al Molo (sea front) or in any of the village???s trattorie on the fishing pier.
Have a nice time.