If you live in Madison or are visiting, be sure that Jolly Bob's is on your list of bars to stop by. It provides a great friendly experience with good Caribbean music, unique mixed-drink selections, and one of the best outdoor patios to be found.
I can't stress the outdoor patio enough, and hopefully when you go it will be during the summer so that it is open. They have a grotto with large tables to seat 4-6 friends and a very large table in the corner which can cater to an even bigger crowd. The staff is warm and polite, and the mood always begs conversation. Even the bar inside, while not as interesting as the outdoor patio, is a great place to stop in for some drinks.
The drinks and food can be selectively good though, so be wary and ask questions. I ordered what I thought was going to be a casual fun Caribbean drink only to find out it was like drinking Bacardi 151 as if it were a sipping whiskey. The food was fine, but nothing to write home about. Still, all these things are made up for by the atmosphere and it's a cool place to introduce friends to.