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) Prosecutor James Blackburn, in closing argument in the Fatal Vision murders trial:
If in the future, you should cry a tear, cry one for them [the murder victims]. If in the future, you should say a prayer, say one for them. And if in the future, you should light a candle, light one for them.