The first two bands are more "ska punk," with some screaming (a la death metal) and head banging (the people in the mosh pit were loving it!). The Pietasters were more classic ska (as I understood it, at least compared to these other bands). Essentially, ska is similar to reggae music but with a little bit of big band or R&B sounds (since there are brass instruments in the bands, like trombones and saxophones).
While listening to the music, it definitely brought back memories of movies like 10 Things I Hate About You, Clueless, and Never Been Kissed. I also thought of No Doubt's early stuff, like their song "Spiderwebs" (but they aren't known for ska).
So what do you think of ska music?