Villa Carlotta
in Tremezzo offers great views of the lake from its large gardens which are famous for the wide varieties of plants. The villa is also a museum containing a number of sculptures and artworks
Boat Trip
Take at least one Boat Trip. The most popular tourist towns seem to be Bellagio, Menaggio, and Varenna. Gravedona and Domaso in the north and Bellano, Lenno, and Argegno mid-lakeare also worth a stop no more than two hours required for each.
Go up the funiculare hillside trolley. From the top you can enjoy the spectacular view, go to Brunate, or hike over to the Volta Lighthouse for an even better view.In Como, one of the really spectacular old lakeside villas is an art museum and is an easy walk from the Como boat ramps.
Try a round of golf or tennis at the Villa D'Este or Monticello golf clubs, or some water sports on the Lake. There are two locations that rent motor boats. Lower horsepowers do not require a boating license.
More water sports: in most of the lakeside towns, you will find opportunities to rent various kinds of boats. Many towns also have sailing and/or kite surfing schools. Water skiing is possible from some towns.
Go for a long walk in the mountains. There are various routes, for instance starting from Menaggio or Dongo. Most offer spectacular views across the lake and sometimes it is even possible to see both Lake Lugana and Lake Como from the same place, such as Monte Grona. The tourism office in Menaggio has a wide selection of possibilities.
Gelato
Many of the small towns around the lake have excellent gellaterias. This dessert/snack is wonderfully flavorful and perfect for enjoying from a bench at the side of the lake.
The Lake Como Greenway is an almost 4 mile walkway on the west side on the lake. While some parts are not lake-front, it is mostly lake-front and its route near Bolvedro/Tremezzo goes thru a very nice lake-front park. The best towns to join the green way are Lenno and Tremezzo.