I'd cosign heading to the North End for a meal at some point. You can't go wrong there, but Nico and Taranta are a couple of my favorites. The South End is also a nice area to explore for dinner and has a diverse range of options (and JJ Foley's is a good pub there that has a long heritage).
For Irish pubs, I agree about the Black Rose for its liveliness, or if you want to go off the beaten path for the best beer bar in Boston (and definitely not touristy), check out Publick House in Brookline. Harvard Sq. has Grafton St. if you want to explore that area. If you end up in the mood for cocktails, Drink in Fort Point can't be beat, as it was named the world's best. The Liberty Hotel is a unique spot, because it used to be a jail. The Seaport is the new hot area and has some nice spots like the Harpoon Brewery, Legal Harborside (especially good when it's nice out), Strega, etc.
For autographs, your best bet is probably to stand near the Celtics tunnel before or after the game. There are usually a bunch of other fans crowding around there, so you'll need to jockey for a good position. In the past, standing near the entrance before the game was a strategy but I'm not sure where the players come in now because of the construction.