Boston is one of the northeastern United State's most historically significant cities. The Boston Tea Party, Paul Revere's midnight ride, and The Battle of Bunker Hill all happened here. It is hard to escape the cultural significance of places as one is just walking down a cobblestone street in the North End. Boston is an American History Buff's dream destination. There are many tours and reenactments that centralize on this theme and almost any of them are worth the few dollars to take one.
Boston also has plenty to do for those of us that aren't so interested in events that happened 375 years ago. From the upscale shops on Newbury Street (Boston's answer to New York City's Madison Avenue), to the breathtaking views that can be seen from the top floor of the Prudential Building (the highest public observation deck in Boston); there is certainly something for everyone.
Boston is the home of two recent championship sports teams (the Red Sox and the NE Patriots), so it is also the optimal place to bring any avid sportsfan. Tickets to events at the historic Fenway Park (built in 1901) are often sold out, but there is a daily tour available for about /person of the ballpark if one would like to go inside without paying exhorberant scalper's fees.
Boston's maritime history is also prevalent here, since it rests on the Harbor. Cruises of the Harbor Islands and other day trips are often a nice thing to do, even if you live in the city and are just looking for a day escape.
Quick Tips:
A plethora of discount coupons and local event listings is available at the Visitor's Center located on Tremont Street on the edge of Boston Common. The Boston Historical Society (located next to the Old South Meeting House on State Street) also has coupons and event listings, but also offers a free walking tour for the first 50 people to show up at the given times (which vary by season).
Best Way To Get Around:
The MBTA public transportation system can be confusing for a first-timer in Boston, but is definitely the cheapest and easiest way to get around. The T costs .25 per token per ride, but stops running at 1:00 am every night so make sure you schedule your activities accordingly. Also, keep in mind that the T becomes impossibly crowded at rush hours or Red Sox home game times.
Driving in Boston is confusing (at best) with almost a million construction projects going on simultaneously and changing traffic flows all the time. Even if you have driving directions, do not assume that they are right since things can change overnight. On-street parking is difficult if not impossible to find, and garage parking in the city can be very expensive (+ a day).
There are several tour companies that stop and pick up at the popular attractions. Most of these start from either the Prudential Center next to the Aquarium on the Waterfront.
Boston is not a very large city, so most attractions are in walking distance from one another. From the North End to Copley Square is about a two mile scenic walk. Walking might be your best bet for nice days.