A nice way to get some variation into the long runs is to take the bus/metro somewhere far and run back home. Google says it's only about 13 km by car to Vuosaari, but if you follow the coast closely it's much longer.
km 2-4: Lots and lots of new houses in Aurinkolahti (Helsinki's own Santa Cruz) before a dive into a green area at km 5-6 (roughly resembling Helsinki central park). Over the vuosaari bridge at 7-8, and into Marjaniemi, an older housing-area around km 8-10. At km 12 you can look at the rich people who are envious of the even richer people, because they have a nicer RIB at the pier just down from their (multi?)million-euro villa. More lots and lots of new houses at "Eastend", a newly built area at km 14-15. The houses are built to look like (large) cottages in the archipelago with a grey weather-beaten-wood look to the outside. However closer inspection reveals it's not wood, just a paneled grey-painted wall. I wonder if admiral Cronstedt would approve? The Iraqi embassy at the 90-degree bend between km 16 and 17 looks as if nothing ever happened, with a well groomed lawn and flowers at the front. Gloves on for the windy kulosaari-bridge at km 18 which offers a nice view into the city center - you can easily count 5-6 churches another half dozen landmarks from here. The view would be even nicer without the architectural concrete-wonders of merihaka at km 20. Just after km 21 the restaurant on tervasaarihas put up a cheesy advert featuring santa-claus and santas-little-helpers. Since the pace was a slow 6:30/km-ish, I decided to quit at 2 hours 20 minutes, or 22 km.
