Giraffes? Giraffes! was a great example of it (and "I am Shimer..." in particular hits all the points). But there's kind of two forms of math rock, with the other being more rock-ish (from groups like Minus the Bear, Forward Russia!, or The Dismemberment Plan). Mutiny on the Bounty is more on that end of it, they sound almost like an emo group but with plenty of angular and prog elements.
Math rock is a rhythmically complex, often guitar-based, style of experimental rock and indie rock acts that emerged in the late 1990s, influenced by progressive rock bands like King Crimson and 20th century minimalist composers such as Steve Reich. It is characterized by complex, atypical rhythmic structures (including irregular stopping and starting), counterpoint, odd time signatures, angular melodies, and extended, often dissonant, chords.