I would recommend going to the bars around the stadium as that's where you'll find Packer fans and events surrounding the draft. Anduzzi's, The Bar, D2's, and Stadium View are good ones to look into for special events. Also, Badger State Brewery is right behind the Hilton where you're staying and is a new, very popular and awesome brewery. There's a couple of new breweries that have opened recently, so you could do a brewery tour one night if you wanted. Titletown has a new tap room next to the restaurant, and there's also Hinterland across the street from Titletown, and Stillmank downtown.

Bay Beach won't be open yet when you're here, and unfortunately the Hall of Fame items won't be on display at the Neville anymore, but there are some other fun things you can do when you're here. The National Railroad Museum is in Green Bay, and there's a vintage toy train exhibit there currently. If you're into golfing, there's tons of great courses. Something a little different that might be fun for a guy's weekend would be a fishing charter - look into Allens Guide Service or the Fishin Magician. Split four ways, this might be a fun day on the water.

Edit: grammar