Mac rebooted, don't know why

[LuKreme]

Somewhere in here, my MacPro rebooted.  I don't know why though.  This  
is what is in "All Messages":

22-Mar-08 01:08:42 /System/Library/CoreServices/backupd[75150] Backup  
completed successfully.
22-Mar-08 01:10:14 natd[73612] failed to write packet back (No route  
to host)
22-Mar-08 01:10:14 natd[73612] failed to write packet back (Host is  
down)
22-Mar-08 01:11:33 com.apple.launchctl.System[2] fsck_hfs: Volume is  
journaled.  No checking performed.
22-Mar-08 01:11:33 com.apple.launchctl.System[2] fsck_hfs: Use the -f  
option to force checking.
22-Mar-08 01:11:44 com.apple.launchctl.System[2] launchctl: Please  
convert the following to launchd: /etc/mach_init.d/chum.plist
22-Mar-08 01:11:44 com.apple.launchctl.System[2] launchctl: Please  
convert the following to launchd: /etc/mach_init.d/ 
dashboardadvisoryd.plist
22-Mar-08 01:11:44 com.apple.launchctl.System[2] launchctl: Please  
convert the following to launchd: /etc/mach_init.d/pilotfish.plist

  $ uptime
  6:37  up  5:26, 2 users, load averages: 2.21 0.90 0.47

My initial suspicion was a power outage (I am between UPSs right now)  
but the clocks on the oven and microwave were not reset.

Where else can I look?

-- 
The Germans wore gray, you wore blue.