you must have boiled potatoes, and 2 boiled vegetables with the meat. usually it's carrots or turnips, and the ubiquitous cabbage.
you could do a tray of other roasted root veggies or sauteed baby veggies. everything from carrots, beets, leeks, onions, rutabagas, squash, brussel sprouts, stringbeans, peas, even baby bok choy, etc..
roasting is easy: fairly even sized pieces, tossed in evoo and s&p, and roasted in the oven at 350.
for sauteeing, i just melt a half stick of butter into a cup of chicken stock in a wok, then add thinly sliced garlic, s&p, and bring to a foamy boil, then toss in the baby veggies. after they've soften just enough, remove them to a bowl, reduce the liquid in the wok and pour over baby veggies.
some other sides you might offer, for an appetizer, try irish cheddar cheese on stone ground whole wheat crackers, topped with a dollop of spicey brown mustard, and chopped raw onion. you'll need to keep this tray near the beer station.
how about smoked salmon, on irish brown bread (like pumpernickel) toast points, with a chive cream cheese.
or an offering of black and white puddings, grilled or griddled, and served with mini potato or oat rolls and butter sauteed onions.
and whole tomatoes that have been topped and sprinkled with herbs du provence mix, then baked. you could also scoop out the tomato a little and add the herbs mixed with some crispy irish bacon lardons.
another side you might try are northern irish potato pancakes for boxtie. (pronounced box-tee). i don'y have a recipe, but if i remember to bring it in, i just got a new irish cookbook. i'll post some recipes on monday.