Microsoft SQL Server 2005 - 9.00.5069.00 (X64) 
	Aug 22 2012 18:02:46 
	Copyright (c) 1988-2005 Microsoft Corporation
	Enterprise Edition (64-bit) on Windows NT 6.1 (Build 7601: Service Pack 1)

use mydb
go
create table [#t-1-2-3] (n int)

use tempdb
go
select name from sys.objects where type='U' and name like '%-%'

name
--------------------------------------------------------------------------------------------------------------------------------
#t-1-2-3____________________________________________________________________________________________________________0000000BEF98

(1 row(s) affected)

select object_id('tempdb..#mytable')

select object_id('tempdb..#t-1-2-3')

select object_id('tempdb..[#t-1-2-3]')