Contemporary is a very vague word, and you will get some answers from as early as 1901 until today.
I'd second the Danzas Argentinas (if it its in your time frame). The first one is hilarious, the second one is beautiful, and the third will definitely reveal techniques you have never ever played before. It's such a biting piece - I played it for an RCM exam, and it probably took my mother (who just like beautiful sounding music

) to enjoy the piece... part of it was probably me playing it 1/4 of the speed for a few hours a day, but the sounds of it grew on her. I'd agree, listen and look through a score at the same time.
If Ravel is being suggested, I'd also suggest Debussy - ANY of his preludes. There are definitely the crowd and forum favorites, but they are all extremely special pieces. This is another example of two sets of pieces where you really have to dig to find what makes them beautiful. Some of them can just be 'played' and still sound decent (La Fille aux Cheveux de Lin, la Cathedrale Engloutie), whereas others (like Feux d'Artifice, Danse de Puck, les Sons et les Parfums Tournant dans l'air du Soir, Terrace des Audiences de la Claire de Lune, Brouillards, Feuilles Mortes, etc, etc, etc) REALLY require you to analyze and interpret. None of them are nasty difficult like Liszt Etudes, but, similar to the Ginastera, they really stand on their own.
With that in mind, anything by Debussy and Ravel are good! Griffes also has some really sweet stuff (I feel like I always hear an echo in a canyon when I mention his name... barely anyone knows his stuff!! And it is truly really good!)
Liebermann's "Gargoyles" is very good - but I really don't know what kind of music you are playing now, and these likely will be extremely difficult. I have a big reach and the fourth one was KILLING me when I was trying it out.
Bartok has two Roumanian Dances op8a (correct me if it is not these), and the first one is really good. It's got an eccentric march like rhythm, goes into some very convoluted harmonies and melodies, and is in the form of a Rhapsody (basically it has the fast-slow-fast, but the slow section is very hypnotic, mystical sounding, and is just awesome).
Khatchaturian's Toccata is mentioned pretty often on the forum (not as much recently), but is a straightforward, and effective piece. It's got some very rhythmic components to it, and it honestly is just a catchy piece.
Eummmm.... who else here. If you want to destroy a piano, and can find a Flautist and Cellist, play 'Vox Balanae' by George Crumb. That was probably my favorite piece I've ever played in my life, and since the Flautist was doing her Master's Thesis, she knew the background of the piece inside out. It's ridiculously good, makes VERY good use of extended techniques, and it almost has a story arc to it that an audience can grasp. That is a pretty contemporary piece, isn't Lisztian-difficult, but takes quite a bit of coordination of the glass rods, chisels, paperclips, etc. etc. My teacher was probably holding back tears when we were rehearsing the piece lol.