Note that you can use a "real" table name in tempdb; that is, a table name that does not begin with # or ##. The table will then remain until you drop it or tempdb is recreated.
You could also have a process that periodically dropped any non-temp table in tempdb that was created more than 120 minutes ago.
SQL DBA,SQL Server MVP(07, 08, 09) A socialist is someone who will give you the shirt off *someone else's* back.