Assuming all of your buddies have a serviceable dining room table, may I suggest you make yourself a table pad? It is a dirt cheap and super-portable solution that gets the job done, albeit with low "wow" factor. I have been using this since February at various peoples' houses with great results:

It is a piece of automobile headliner foam covered with cotton velveteen fabric, obtained from my local JoAnn's Fabrics for about $45. I have since found that the dye from the velveteen tends to bleed a bit onto your fingers (and perhaps even your cards), and so I have made a second one using faux suede (polyester) which has replaced this one. It was actually cheaper because I used a 40% off coupon for the foam and found the faux suede in the "Value Flat Fold" bins.
The pad is sized to exactly fit the table with one leaf extension in (in the picture I have two leaves in), 81" x 42". This size seems to be close to the size of most of my friends' dining room tables as well. If the host's table is smaller than the pad, I use clear packing tape to fold the edges around the table and tape them to the underside. The second pic shows the pad rolled up, which is how I transport it to friends' houses. The edges of the velveteen are just folded over the edges of the headliner and then glued to the foam side (bottom) with spray adhesive. I did not use any glue on the playing side between the headliner and velveteen except for a very little around the edges--this to avoid any permanent wrinkling problems in the playing area.