Meant to post this earlier, I was given 2 promo cards at the J.W. Sweetman's bar at the RDS.
[img:1jd85ze8]http://oi60.tinypic.com/330sc9d.jpg[/img:1jd85ze8]
The first is pretty obvious, they said they have a stack of them to give away and will probably give them out as you're leaving the brewpub (to entice you to come back).
The second one then obviously says you get a free growler after buying 4 pints but they will also give you a free growler [i:1jd85ze8]fill [/i:1jd85ze8]if you already have a growler bottle. Not sure if they will fill any growler or if it needs to be a Sweetman's branded one.
I think you can ask for those cards from the bartenders as well.
