Hope this is not too off-topic: we collected a couple of things to do in Vienna if you are staying over the weekend. Feel free to extend the list! 
Spots are grouped by geographic locations into three parts.
Part 1
(1a) Ikea roof top
Nice view, you can go there for free also without shopping. Next to train station “Westbahnhof”
(not the central train station).
Mo-Fr: 09:30-20:00 Uhr, Sa 09:30-18:00
(1b) Shopping street: Maria-Hilferstraße
Example for a successful project to reduce car traffic in the city:
2006:
2015:
(1c) MQ Libelle
Roof top bar in the MQ (musuems), accessible also without consumption
(1d) Restraunts around
Lolo & Lola (Filipino cuisine)
Part 2:
(2a) Spittelau: garbage incineration plant
Built by the architect Hundertwasser.
https://goo.gl/maps/B5EPwAjuDgj6Mm6t7
(2b) Karl-Marx-Hof
Karl-Marx-Hof (English: Karl Marx Court) is one of the best-known Gemeindebauten (English: municipal housing complexes) in Vienna, situated in Heiligenstadt, a neighbourhood of the 19th district of Vienna, Döbling.
Tour at 1pm every Sunday, 10 EUR, not sure if they offer an English tour:
(2c) Winery (“Heuriger”)
You can find wineries west of “Heiligenstadt”, accessible either by walking or a bus.
Search on google maps for “Heuriger” or “Buschenschank”. Check time tables:
https://goo.gl/maps/9gfoY7wqQ3BJ6ET79