I hit the pit for a front row view of LCD Soundsystem's blistering set on Friday night. Frontman James Murphy's 2007 opus, Sound of Silver, is a top 10 record-of-the-year for me, but when he picked up a cowbell and shouted out, ''Daft Punk is playing in our house!'' it was super thrilling because it was actually true. An hour later the opening chords to ''Close Encounters of the Third Kind'' alerted the crowd that the French space-helmeted duo had landed on the mainstage for an out-of-this-world terrestrial dance party.