This is a song about a girl who wants space legos (In other words, my kind of girl). Here's a typical conversation in Palace Of The Brine Studios regarding this song:
Judah: Hey Rick, are you playing "Jack and Dianne" again?
Rick: Shut the fuck up! You know damn well what I'm playing.
Judah: Sounds like "Jack and Dianne" to me.
Rick: God damn it! It's that one... you know that one...
Judah: "Jack and Dianne"?

I think you get the gist.