In a secluded park in the youthful 7th district of Austria's capital, this quirkily cool hotel, with its reception on the top floor, has been cleverly converted from a 1970s student hostel. But to associate it with student digs does it a disservice, for step inside this nine-storey building and you'll find not tatty posters and stained carpets but a paean to the circus.
The hotel's design team, Dreimeta, has conjured a heady mix of transience, bohemia and showbiz, with bathroom-cum-dressing rooms, vintage sofas and antique leather suitcases dotted everywhere. Even though it won't be fully completed until next year, there is plenty here to reward the guest.
Each building in the 25hours group has its own identity. The version in Hamburg's HafenCity, for example, sits by the docks and has a maritime theme, while one of the hotels in Frankfurt has been designed in co-operation with the jeans giant Levi's.
What they have in common, currently at least, is the German language, a dynamic urban budget chic and a great sense of fun.
In Vienna, three new glass floors, housing 34 suites, now sit on top of the original six-storey building, while the former students' quarters beneath are being remodelled to fit the hotel's contemporary, artisan feel. By next spring, a further 187 rooms will have been added, as well as a spa, a gym, conference areas and a restaurant seating 120 people. Though the bedrooms won't be as large as the airy suites above, most will offer views of the Viennese skyline.
The Dachboden (Loft) is a relaxed rooftop bar and terrace with views over Weghuberpark and the city beyond. It has already become a favourite after-work haunt and weekend hangout. Until the hotel gets a fully functioning restaurant, the Dachboden is offering sustenance in the form of Brettljause, a regional cold-cut speciality served on a wooden platter that sits comfortably with the hotel's fun, informal feel.
The hotel staff are young, energetic and friendly; the atmosphere is party-like and the guests seem smart and interesting.
25hours Hotel is on the western edge of Vienna's city centre – the Innere Stadt – just outside the Ringstrasse that encircles it. You can reach the magnificent St Stephen's Cathedral (Stephansdom) on the number 46 tram in just a few minutes, but it doesn't take much longer to walk, taking in the sweeping Austrian Parliament building en route. Alternatively, turn left and stroll straight into the vast Museums Quarter, home to renowned institutions such as the Leopold Museum, with its numerous works by Egon Schiele, the Museum of Modern Art, and the Kunsthalle – a diverse array of restaurants, cafés and bars.
Vienna is a city of parks and gardens – 280, in fact – and the hotel has free bike hire to let you explore them, and to whizz around the capital's compact centre.
Walk into any of the suites and the circus theme hits you like a custard pie in the face. Seemingly printed on the wallpaper above the beds are fire-eaters, sword-swallowers, jugglers, acrobats and tigers – all given a slight but unnerving dark edge by the Berlin artist Olaf Hajek.
Each spacious suite includes a kitchenette. The furniture has a simple, stagey and temporary feel, as if it has been salvaged from an artist's garret or put together by a prop builder (although, thankfully, the large and comfortable bed is an exception).
The flat-screen TV is perched on a pile of leather suitcases, the bedside lampshade has been crocheted and the sliding doors of the wardrobe roll on cartwheels to resemble a circus wagon. The bathroom doubles as a dressing room with a showbiz-style lighted mirror.
You are made to feel that you are part of a travelling circus, in town for a week and then moving on. Anyone who has ever wanted to be on tour in a show or a band will love it. Expect star treatment.
25hours Hotel, Lerchenfelder Strasse 1-3, Vienna, Austria (00 43 1 521 510; 25hours-hotels.com/wien).
Double rooms start at €130, room only.