They're a mainly indie band with electronic influences - no, don't worry, not techno-y/dubstep electronic. Don't expect that stuff from me. Their band name is slang for drive-in movie theaters (passion pit, get it?) and their first album, later to be referred to as "Chunk of Change", was a belated Valentine's Day gift to the lead vocal's (then)-girlfriend. What a way to start out, right?
This song in particular is what every song should be. It has a great beat and great lyrics with a person that actually has a great voice singing them. This is one of those "thinking" songs, though - you have to think about the lyrics to understand them ("They crowd your bedroom like some thoughts wearing thin against the walls, against your rules, against your skin"). I can honestly say that it is completely worth it.
Want to try it out? Here's the video. Don't like it? Maybe next time, I'll get it right.