Around the turn of the millennium, Jeff Tweedy merrily nurtured a reputation as a contrarian. How best could a man, sanctified as the archetype of what was once called alt-country, confound his fans? With antsy powerpop? Radio static? Fifteen-minute ambient noise jams? The recruitment of a fiendish avant-jazzer to take over on lead guitar? A song for a Spongebob Squarepants movie?