They go and get more obnoxious. OK Go's (of course OK Go's) Damian Kulash re-enacted the "surprised kitty" with an audience of 700 people on a "how to create viral content" panel. Hopefully what followed was a re-enacment of this.
Damian Kulash is a microcosm of SXSW. Both were associated with music at one point, and now both have morphed into some amalgamation of music and internet videos. It's safe to say that the music part is way less self-indulgent, and way more entertaining.