Sloan just quietly released a collection of b-sides and rarities they're selling at http://www.sloanmusic.com/ for $9.99. It's 26 tunes, and the first is the original version of Underwhelmed.
If Sloan's embeddable player worked, you can hear this version of Underwhelmed above. I've never heard it before, even though the song we all know and love made my Ten Canadian Tracks list.
Is it me, or did Underwhelmed sound an awful lot like Sonic Youth's Kool Thing before they changed it up?