Modest Mouse will be performing at the opening night of Macworld at a concert entitled Macworld | iWorld Opening Night BLAST. The show will be taking place at The Warfield in San Francisco on January 25, 2012. Tickets are available now it seems through some kind of registration process, for what I believe is $35 (but this may be on top of the ticket price for the Macworld expo being held at Moscone Center). Also it sounds like there is a special deal on at the moment, and the price will be going up tomorrow.
The Macworld | iWorld is being held January 26 - 28, 2012 at the Moscone Center in San Francisco and is the ultimate fan event for those who use, create, and love Apple products.