How to give each screen session a description?

Hi,

When I run the following command I got a number for each session.
Those numbers are not descriptive. Is there a way to associated some
string to each session, so that I can easily remember what each
session is doing?

~$ screen -x
There are several suitable screens on:
	4286.pts-35.markov	(11/28/2011 10:21:45 AM)	(Attached)
	3569.pts-9.markov	(11/28/2011 09:27:31 AM)	(Attached)
	32528.pts-40.markov	(11/10/2011 03:23:21 PM)	(Attached)
Type "screen [-d] -r [pid.]tty.host" to resume one of them.

-- 
Regards,
Peng