Grab a drink at the top of the Pru (Prudential Building, located above the Copley Mall) for a great view over Boston.

Take a stroll down Newbury St for yuppie snob-dom at its finest.

Take taxis (expensive) or the T to get around downtown, as parking is a bear.

Fanuil Hall is a part of Boston's history and should be seen at least once.

The Old North Church among other sites are on the Freedom Trail. You can also take guided tours. Not sure if Old Ironsides is open now but if it is it's worth it. Bunker Hill is also fun. If you like to climb, there's the steps.

Have fun. I'm heading to California and Arizona for 10 days business trip.

Museums? Sports? Music? Food? History? Outdoors? Shopping? Clubs?

I might tell you to visit the new Institute of Contemporary Art on the South Boston waterfront because it's cool and has a great view of the city, but if modern art's not your thing....

My GF lives on the square.

Museum: MUST see the Isabella Stewart Gardner (near the Museum of Fine Arts so you can do that too)

Food: SOO many in Boston. Grab a zagat guide so you can narrow it down to what you want (i.e., your price/cuisine/etc.)

History: Old Ironsides in Charlestown, Paul Revere house in Cambridge, freedom trail.

Go to China Pearl on Tyler St for Dim Sum
And if you like sushi, Ginza on Hudson St.

Museums - yes to Gardner and the new ICA, maybe to MFA depending on time and how much time you really want to spend in museums. Harvard museums are great as well but require a T ride to Harvard Square.

Food - good suggestions in Chinatown below, also explore the North End, uniquely Boston and unfrancheesy Italian neighborhood. South End for trendier spots.

History - It's everywhere. Freedom Trail walk is fun, bring a flask and tip one back in front of Samuel Adams grave on Tremont St. Take the MBTA water shuttle from Long Wharf to the USS Constitution (Charlestown Navy Yard), it's a harbor cruise for a couple of bucks.

Shopping and Coffee Shops - Newbury Street, all the Euro most people can handle and best car watching in the city.