You can create regular user tables in tempdb by specifying the database name in the command that creates the table:
create table tempdb..temptable (...)
or:
select select_list into tempdb..temptable
Regular user tables in tempdb:
Can persist across sessions
Can be used by bulk copy operations
Can be shared by granting permissions on them
Must be explicitly dropped by the owner (otherwise, they are removed when Adaptive Server is restarted)
You can create indexes in tempdb on permanent temporary tables:
create index tempix on tempdb..temptable(col1)