If you want a cool Irish bar the locals go to, try Crossroads near Fenway. Beerworks is good too, with a bunch of microbrews, and closer to Fenway Park. For amazing views of the city, try drinks at Top of the Hub at the Prudential Center. The food is decent, but pretty expensive for what it is, so I'd advise sticking to drinks. Neptune Oyster Bar allegedly has great lobster rolls (hot or cold!). If you have access to a car and want a seafood shack type experience, try Belle Isle. I haven't gone on a Charles Riverboat cruise yet, but they look really fun and lower-key than the duck tour, though I've heard the duck tour is a lot of fun as well. If you want, I can get more specific depending on where you are staying. Have fun!!