Celebrities are fairly regular sightings at SXSW, given that there's a film festival running alongside SXSW Interactive. But it's only recently that the geekier portion of the conference has attracted legitimate celebrities to its packed roster of panels and parties.
Actor Michael Cera ("Juno," "Arrested Development") stopped by a Sunday night party at The Mohawk, thrown by StumbleUpon and digital agency The Barbarian Group. He took part in an onstage jam in the process.
Cult hero Pee-Wee Herman (in real life, comedian Paul Reubens), who has made the use of Twitter and Foursquare a big part of his recent revival in pop culture, appeared at several official and unofficial SXSW events and was surrounded by admiring (or amused) fans just about everywhere.
Actor and comedian Rainn Wilson (far left) was at SXSW mainly for its film festival, in order to promote his new movie. But he swung by the Interactive portion of the festival as well; here, he sits in for an interview conducted by Facebook at cable channel IFC's pop-up headquarters.