-On the Seawall you have The Spot which has several different places all in one. (Drip is a nighclub stlye place that often has a cover band, Rum Shack for mixed drinks, Tiki Bar and a Tequila Bar I forget the name of as well as the Spot itself for food.)
-Right down the street is Brick House. (Their Drunken Pork Chop is great)
-AVOID THE PLEASURE PIER!!! That place is a tourist trap and there isn't anything there for you guys.
-There's a club/bar (idk) at the San Luis hotel that is supposed to be nice.
-Right at 25th (Rosenberg) and Strand there's a place called Crows that gets pretty popular some nights.
-There's a country bar called Buckshot that's on Market and 24th (between 24th and 25th)
-Murphey's Pub is a good place to hang out and they have really good pizza. (22nd [Kempner] and Mechanic)
-Of COURSE you should hit up Whispers and see if the one legged stripper is working.
(20th and Mechanic)
If you want to go fishing there are several charters. Galveston Party boats has some tours that are inexpensive but the boat holds something like 80 people. If you're after something more for just your group call Green Water Guide Service (281)799-5728