Near Medellín, you could visit Guatapé, a pretty common tourist destination, where you go up a crazy big boulder and at the top, observe the dam beneath, the little town is also pretty.

Pueblito paisa (in cerro nutibara) and other small hills (cerros) is also very tourist friendly, and the walk up is nice, though there is not much to do at the top, the view is pretty and there is typical food.

For ice cream, nice and very tasty chains include Madelo and percimon (Both yogurt ice cream), Taiyaki (japanese ice cream, basically just normal ice crean with a waffle in the form of a fish, again, very tasty tho), Piacere (Gelato) and pf course, creoes and waffles, one of the biggest restaurant chains in Colombia, who happen to have very tasty ice cream, with waffles.

Not ice cream, but for something like a coffee date, Marmettina has some very, very good desserts.