Difference In Creating Temporary Table By #table And ##table

Banti writes "IF i create temporary table by using #table and ##table then what is the difference. i found no difference.
pls reply.
first:
create table ##temp
(
name varchar(25),
roll int
)
insert into ##temp values('banti',1)
select * from ##temp
second:
create table #temp
(
name varchar(25),
roll int
)
insert into #temp values('banti',1)
select * from #temp

both works fine , then what is the difference
waiting for ur reply
Banti"