2010-09-10 13:18:29.01 spid5 Starting up database 'tempdb'. 0
2010-09-10 13:18:29.21 spid3 Recovery complete.
The first line states that the tempdb is starting.
The second line states that the Recovery is Complete. When SQL Server starts up, it tries to recover all the databases. This message means that SQL Server has completed recovering all the databases. It is not specific to tempdb.
Pradeep Adiga
Blog: sqldbadiaries.com
Twitter: @pradeepadiga