Ashlee Simpson's Postpartum Party

12/2/2008 5:30 AM PST
Unless Bronx Mowgli Wentz ages 20 years and 46 weeks by New Year's Eve -- he'll be spending it sans his emo mom and pops.

Ashlee Simpson and Pete Wentz are giving up diaper duty for the night to host Pure Nightclub's New Year's Eve party in Las Vegas.

As long as they don't leave him with Jessica...